Studying for finals

if you decreased a planet's semi-major axis, what effect would that have on it's period?

Which element provides strength to the exoskeleton of clams and oysters

Resperation is a way to release carbon back into the atmosphere

In trying to determine whether dna or protein is the genetic material, hershey and chase made use of which of the following facts? a) dna contains sulfur, whereas protein does not. b) dna contains phosphorus, whereas protein does not. c) dna contains nitrogen, whereas protein does not. d) dna contains purines, whereas protein includes pyrimidines.