My last question its easy but i dont get it lol help plz

Which traits do human embryos have that link them to a common ancestor with fish and reptiles? a. scales and tail b. gill slits and scales c. tail and gill slits d. hair and tail

Sulfuric acid (a component of acid rain) reacts with limestone (calcium carbonate) to produce calcium sulfate and carbon dioxide. this damages buildings and statues made of limestone. which solution of sulfuric acid will damage these structures more quickly? a. 0.001% b. 0.005% c. 0.010% d. 0.015%

Can someone me with questions 12 and 13 plz.