Which of these describes the structure of a nucleic acid

What are the two causes of density in deep current waters? a. salinity (how much salt) of the water and high temperaturesb. salinity (how much salt) of the water and low temperatures c. oxygen content of the water and high temperatures. d. oxygen content of the water and low temperatures

What tool do geneticists use to predict the outcome of genetic crosses? a. karyotype b. punnett square c. centrifuge

What are the four stages of cell signaling?