What’s the element of the picture shown?

Hydrogen

Explanation:

I am assuming the two circles in the middle are the proton and neutron.  If so, you only have 1 proton.  On the periodic table, the periodic table with only 1 proton is hydrogen.

You can tell how many protons an element has by looking at its atomic mass.  Hydrogen has an atomic mass of 1.

what is the average time it took the car to travel 0.25 meters?

⇒ 2.23 seconds

what is the average time it took the car to travel 0.50 meters?

⇒ 3.13 seconds

it would be b. 6co2 + 6h2o --> c6h12o6 + 6o2