Human sperm and egg cells have chromosomes.
A. 42

B. 21

C. 23

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels

Read the article and use the information to answer the questions that follow discovering the structure of dna explain how the discoveries by rosalind franklin watson and crick build an accurate model of dna done

This is the nitrogenous base only found in rna