good evening, i'm antonio mora, this is al jazeera america. presidential contest in the united states on tuesday could lead to a decisive day for both parties. >> tomorrow's the day we'll start the country plenty of enthusiasm from senator marco rubio - successes and regrets as his campaign searches for a win withdrawing forces from syria, the factors that have russian president vladimir putin changing strategy. >> what the intention is is to look for traces of methane gas. a new mission to mars - a two-pronged attack to better understand if life ever existed

on the red planet the presidential candidates are gearing up for a day of primaries that could bring clarity to the race for both parties or throw the contest into further chaos. voters go to the polls in florida, ohio, illinois, north carolina and missouri, with hundreds of delegates at stake. as david shuster shows us, the day could be the last stand for at least one contender. >> tomorrow is the day we'll shock the country and do what needs to be done. we'll win the 99 delegates in florida marco rubio campaigning in florida as if his political life is at stake, and it is. marco rubio trails donald trump by 2-1 in a winner take all home

state. without a win, marco rubio may be staying home for good. also at stake primaries in missouri, new orleans, ohio and illinois. in ohio, the second winner takes all contest, texas senator ted cruz invoked adversaries in both parties. >> if you don't want to see donald trump as the nominee, clinton as the president. i ask you - come stand with us. >> polling suggest cruz is trailling badly in ohio, where the governor is making what could be his last stand in the 2016 race. with poignant words for donald trump. >> this country is about coming together, not tearing one another down or having fist fights at a campaign rally. that is not what america is. >> it is what has happened at many of trump's rallies, after the candidate cancelled a

chicago rally on friday, a few clashes broke out between protesters and supporters. trump in part blamed bernie sanders. . >> someone will stand up, say something, and they have a bernie sign, bernie's going nowhere. probably given to them by bernie. >> despite scenes like this at a trump event last week in north carolina, donald trump insists his rallies are love fests. >> do you know how many have been hurt at the rallies. i think basically none, other than someone was hit once. there's no violence. >> no violence, but lots of enthusiasm in ohio, as bernie sanders blames hillary clinton for trade deals costing hundreds of thousands of manufacturing jobs. >> the difference between secretary clinton and myself, is not only did i vote against every one of these disastrous

agreements, i led the opposition to them. sanders may have an uphill battle in ohio, where polls have clinton ahead. polls suggest it's too close to call in illinois. in the western states where hillary clinton grew up. >> we come out of the elections tomorrow with a win at our backs. we have the way forward to be able to start talking about not only unifying the democratic party, but unifying our country. >> hillary clinton enjoys a huge lead in the polls in florida, and acted like the front-runner on monday even though the threat builds. after the vote, talks of unifying the country and the party may have to wait the stakes are huge for every candidate tomorrow. as david shuster touched on no one has more to lose than marco

rubio. as michael shure reports from miami, florida are could be the sight of marco rubio's last stand during the snows of iowa and new hampshire political watchers new it could come down to the sunshine state. >> all eyes are on florida, and you see the democratic and republican candidates. >> reporter: this is a long-time polster. >> the hispanic vote has gotten away from the republican party. >> reporter: that is why republicans had high hopes for favourite son senator marco rubio. former ambassador was a she'd bush advisor. after jed bush dropped out, i thought there would be a big push. margins were worse today than in the past. >> reporter: now, ted cruz is giving him trouble, here in the

swing statement. -- state. >> trump gives them anger and anger and without that you are not winning. make cruz a little angrier than marco, he has been doing well. >> reporter: in a shrinking field, notably from the race of jed bush. he has won endorsement. >> i didn't do as well as i wanted to. i was disappointed when i got home. >> i think of rubio like republican john edwards. someone who had a lot of same humble origins elected in an important state. but there was almost an allegation of superficialism, overriding ambition, trumping anything else. >> i would have told them not to run in 2016. two guys from florida, it's a bad idea. >> amid calls for him to lead

the race and polls indicating the opposite. rubio stressed he will win florida, and then win the nomination. >> i believe with my heart that the winner of the florida primary will be the nominee of the republican party. >> the statistical odds are getting smaller. a poll shows in order to capture florida, marco rubio has to win 30% of the votes to be cast. a call order. carlo supports his friend, but is realistic. >> he admitted publicly that winning florida is important. i assume that after florida, win or lose, he'll evaluate the decision. >> i always believed god blessed america, and the greatest days are yet to come. >> marco rubio needs tuesday to be his greatest day. ohio governor john kasich is

hoping for a big win in his home state tomorrow. he's printed as a moderate alternative in the race for the republican presidential nomination, is that the case. lisa stark reports from colombus ohio. >> on the campaign trial ohio governor john kasich tries to be positive and polite in what has often been an unruly campaign season. he paints himself as someone that works across the aisle to get things done. a man that tells voters you're special and offers up hugs. >> at the state house, the senate democratic minority leader says the government has not bridged divide. this man represents a school district that the state has tone over. >> he getting a call saying the governor will push a bill to take over your schools tomorrow, just wanted to give you a heads up. no conversations, no hugs, no handshakes, just we're doing d

tomorrow because i say so. >> she also says the governor is hardly the moderate he appears on the national stage. he tried to take away collective bargaining rights from employees in ohio. >> half abortion clinics had to close, supported gun rights and school choice. jason is a supporter for a conservative website culling for a digs to embrace obama care. expanding medicare as a break from his republican roots. >> i don't know anyone could defend that policy as first calorie conservative. when the federal government is 19 trillion in debt. he has change's a poll out way to say it. he has a soft spot for those

that need help. and a big portion is those with mental illnesses. >> russell was worried he would not have an ally in the government. instead john kasich is his champion, allo gaiting $110 million. >> it was tremendous political risk, and some of his party are criticizing today for doing that. but he looked out and saw that people prop in need. >> john kasich is a man of contradictions, criticized from the left and the right, ahead of state of the republican party mimicked the candidates own words to size him up. >> sounds like the porage was too cold, too hot on the other and john kasich was just right democratic front-runner hillary clinton participated in a town-hall-style event in

spring hl illinois. dealing with guns was a topic she discussed. the gun lobby intimidates elected officials and they vote the way they are told. my opponent talk about powerful lobbies in washington. and there's a number. nothing is more powerful than the gun lobby. until we are ready to take them on and hold them accountable, we'll not be in a position to reduce the deaths from the epidemic of gun violence. >> voters should consider a stance on gun control. the national rifle association prayed bernie sanders for one of his positions. >> the justice department is calling on state courts to stop gaoling defenders who failed to pay fines or fees. a letter was sent out to administrators around the country, ruling that it could violate law and erode trust.

courts must give defendants fair notice, and should not use arrest warrants as a way to collect un paid court debts. >> a surprise move from russia, vladimir putin ordering most of his military to leave syria, a move leaving many to react. and a top n.f.l. official tells congress there's a link between concussion sustained by players, and devastating brain disease.

>> these people have decided that today they will be arrested. >> i know that i'm being surveilled. >> people are not getting the care that they need. >> this is a crime against humanity. >> hands up... >> don't shoot. >> hands up... >> don't shoot. >> what do we want? >> justice. >> when do we want it? >> now.

>> explosions going on... we're not quite sure - >> is that an i.e.d.? for the first time an n.f.l. official acknowledged a link between concussion and c.t.e. , a debilitating brain disorder. the statement in a roundtable discussion hosted by the house energy and commerce committee. jeff miller, a senior vice president for health and safety said a link was established. but it was not clear how common a disease was or how likely a person is to get it an-amtrak train derailed in kansas, two people in serious condition. eight cars jumped the tracks on the way to chicago. there was a deformity in the rail and the emergency brake was

pulled. n.t.s.b. is investigating in a surprise announcement vladimir putin ordered his military to withdraw from syria, saying the deployment largely achieved its goals. it's unclear if russian air strikes will stop jamie mcintyre has reaction from the pentagon. >> vladimir putin is essentially declaring victory and beginning to pull ot troops after five months of intervention, one he insisted was all about fighting terrorists, and the u.s. argued was more about propping up the regime of bashar al-assad. >> in the latest assessment of bashar al-assad in syria, the pentagon saw a glimmer of positive news. russia was lamented to striking -- limited though striking isil targets. doing it with gusto, targetting strongholds in palmyra and other

areas. then game the unexpected announcement from moscow. vladimir putin, after meeting with his minister said he ordered a pull out of the main part of russia's forces. saying the goal has been fulfilled. the withdrawal came as a surprise and obama administration were reduced to saying stay tuned. >> i did not see the report before coming out here. i'll have to serve comment before taking a clans to look at it and lake an assessment. >> should we expect the president will speak with vladimir putin. >> i would rule it out. whilst it's withdrawing most of its troops, it will continue to have a presence at a long of time naval base, as well as holding on to newly established air base in syria's latakia province.

that was no surprise to the pentagon, noting that improvements to the syrian base, including the installation of runways and underground fuel tanks indicated a long-term stay. also no surprise, with the oil-dependent economy in decline, the kremlin would need to end the air war. the pace was unsustainable considering russia was not rotating in fresh aircraft nor performing routine maintenance. administrative critics, such as vladimir putin said critics had achieved their goal. of the russians, mccain said: privately the millings accomplished statement by the

vladimir putin is an administration that it was never about isil. the only mission was the regime of bashar al-assad is deniably in a stronger position, while isil is nowhere near defeated jamie mcintyre at the pentagon. kurdish forces in iraq say they have captured a palestinian american man that fought with i.s.i.l. 27-year-old turned himself in. at the time of his surrender he had a large amount of cash, three cellphones and three forms. identification. one was a driver's licence identifying him as mo whommed jamal the newest mars mission has something that sets it apart from others. next, the new push to find out it there is life on the red planet. and how climate change could lead to another great migration in the united states.

. >> rising sea level caused by climate change may cause a mass migration in the united states. a study published in nature climate change looked at the worst state scenario forecast and calculated. and 13 million americans would move to higher grounds if sea levels rise by 6 feet by 2100. half of those affected live in

florida. the newest mars mission started a 7-month trip to the red planet after a launch from kazakhstan. the exo-mars spacecraft left earth's orbit. it is a collaboration between the european space agencies. >> scientists hope the mission can help clear up questions about life on mars. >> we know more about the planet mars now than ever before. there are seven active orbiters on or above the planet. these are from the u.s., european union and from india. recent discoveries included the presence of liquid water. some below the service of the planet. and shed life on how mars's atmosphere was deflighted by solar winds. the big question, whether there was life on the planet, is unanswered. that's why the european and

russian space agencies are sending the exo-mars trace gas orbiter to the planet. it uses a range of sensitive instruments to explore the atmosphere, looking at methane and whether it's used. >> methane is a hot topic. trying to understand the origin of the methane, and where on the service of mars and when and how it's destroyed is important. water has been seen on the surface. i think we need to understand a little better what is the water ipp ventry with debt. if you want to land people on there, they'll need drinking water. >> the mission will drop a small

lander to the margin sfs. it will give it the sundayy to use the lander rover. another two from the u.s. and india are expected in the next two years. the flood of new batter tells us mr about the red planet and its formation in the solar system. >> derek join us from markus phillips. good to see you. so the projected has two stages, how much can we learn about life on mars. what the intention is is to look for methane gas from the atwas fear. through the atmosphere. the reason why it plans to do

this if the osh iter detects, thus indicate ght the possibility for life on mars, the wholly grail for all of this explanation, and the orbital altitude, the platform, is a great location to survey the whole planet for this. the second stage involves a rover. how much do we learn from that. there's more than half-a-dozen spacecraft on mars or in orbit around it. mars is a big enough planet that we can put another lander in some place and find the environment that may have been the environment where life may have come up at some point in mars past. the planet has been sitting dormant for millions of years, hundreds of millions of years, you can look at it like that.

so some changes that may have happened on the surface, or maybe there's a location that has not been identified. having another land are on the surface gives us data to graft a picture of what the early history is right or taking act of what may have been there. you mentioned it's a big planet. and the conclusion that water mists, at certain times of the year is deduced from images taken from an orbiter. with the power, is it that recoveries have not been sent to the right place. >> we pout a lander down near the north pole of mars, and it scraped through the upper layer of soil and was to find permafrost. radar studies indicates that there's an amount of water in the as far as of mars. to have another rover on the

surface helps to look for other pibilityies of environment. >> will we need humans to know for sure if life exists. >> the rovers that we have on the surface are doing a phenomenon job considering they work at a distance. the best equipment is if we put a human there. they can cox up and determine where to go and what to look for. things that machines can't do. >> my next and final question - is the sense so far na what he did is a big step towards human travel to mars. if so, how soon can we get

someone there and back in. >> well, that is a long way off. technology has to be developed to make it safely. no matter what we learnt from scott kelly's trip, which is a huge amount. this really goes a long way to help us figure out that critical question. critical because the idea of visiting the planet - it's a difficult one on the human body physically and mentally, it behooves us to understand it as best we can. >> exciting times when it comes to space. it's good to talk to them about it. thank you. >> thank you, antonio. >> a news discovery could help to explain the evolution of the massive predator, the tye ranna sorous rex. the 90 million-year-old remains were found in uzbekistan. the horse-sized dinosaur had a

large brain and keen hear oings. before this find there'd been a 20 million year gap in the fossil record where tyrana sore awes went from the size of a dog to a school bus. new york mayoral candidate jimmy macmillan said it, but it didn't make him mayor. he closed his pitch, simply, the rent is too damn high. young families, middle class workers, head into the rental market and find prices driven up by lack of availability or