If metals were located in the same period on the periodic table but in different groups, which would have the highest group number

i'm assuming that the correct answer is indeed the first one/ "a"..

space exploration has led to the development and technological improvement of many everyday items. (if this answer is wrong i will find the right answer) : )

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.