Why did hershey and chase label the viral dna with radioactive phosphorous and not radioactive sulfur?
dna contains phosphorus and no sulfur.
proteins contain phosphorus and no sulfur.
dna contains sulfur and little phosphorus. proteins contain sulfur and little phosphorus.

Ablastocyst is a group of cells that forms after a human egg is fertilized. the blastocyst consists of two types of cells. some of these cells will become the placenta. what do the other cells develop into?

What can be said about farmers in highly developed countries? a) they have little or no negative impact on the environment. b) they practice subsistence agriculture. c) they are able to incorporate polyculture into their farming practices. d) they utilize organic farming techniques on a regular basis. e) they rely on large amounts of energy from fossil fuels.

How does friction with the atmosphere affect the speed of an artificial satellite