Question

The U-238 isotope has 92 protons. After it undergoes its three nuclear reactions and turns into a lighter uranium isotope, how many protons are left? a) 92 b) 88 c) 90 d) 89 Which of the following is hypothesized to be responsible for the oxygen in our atmosphere a) self-replicating molecules b) multicellularity c) photosynthesis d) glycolysis

Answer 1

(11)

a)92

U238 decays into U 235 after 3 nuclear reactions, it will have same number of protons left,

(Protons are the same among isotopes of a given element)

(12)

c)photosynthesis

Photosynthesis is responsible for the atmospheric production oxygen