Suppose that cells are grown in culture in the presence of radioactive nucleotides for many generations so that both strands of every DNA molecule possess the radioactive nucleotides. The cells are then placed in new medium (as round 1) with non-radioactive nucleotides so that newly synthesized DNA strands will not be radioactive. What proportion of DNA molecules will contain radioactivity after 2, 3, or 4 rounds of DNA replication in the new non-radioactive medium? Why?

The proportion of DNA with radioactivity after 2, 3, or 4 rounds of DNA replication will be 1/2, 1/4 and 1/8, respectively

Explanation:

In each round of DNA replication, the radioactivity will decrease to half of its previous value, since in each round of replication will synthesize a non-radioactive DNA strand to form the double-stranded DNA molecule in the daughter cells

answer: national resource conservation services

national resource conservation services is the us. based approach that provides technical and financial assistance for natural resource management. nrcs society in conservation of resources by involving in activities like farmland protection, flood prevention, watershed protection, urban conservation, conserves economic and environmental conditions. it conducts soil surveys and implements the policy of natural resources management on the society.

layer 3 is younger than layer 6.