Which statement is true?

a- there are a number of chromosomes on a given gene; all of these actively code for proteins.

b- chromosomes contain many genes; not all genes are actively coding.

c-dna contains a number of segments that code for specific proteins; these segments are chromosomes.

d- the segments of gene found on chromosomes are made of rna, which codes for protein synthesis.

What is the chance of two parents with blood types ab and o producing an offspring with blood type o a.0% b.25% c.75% d.50%

The pharynx is the structure in the body that serves as a pathway of both air and food. how does the body make sure that food does not get into the lungs? the salivary glands secrete enzymes that pull food out of the air pathway. the small intestine pushes the air out of the digestive system. the pancreas breaks down food in the air pathway. the epiglottis closes the air pathway so that food will not enter it.

In many humans, exposing the skin to sunlight over prolonged periods of time results in the production of more pigment by the skin cells (tanning). this change in skin color provides evidence that -