100 points pls help?

When the following equation is balanced using the smallest possible integers, what is the coefficent of oxygen gas? c7h16o(g) + o2(g) → co2(g) + h2o(g) -1 -5 -8 -16 -21

What element breaks down into yttrium-90?

How heavy is thanos? a) 3000 lbs b) all of it c) the price of tea in china d) heavy enough