Cell differentiation occurs when various genes are expressed to a different extent in different cells. what does it mean for a gene to be "turned off," or not expressed?

a. transcription into rna does not occur for that gene.
b. that gene is removed from the cell's dna.
c. the rna for that gene is not translated into protein.
d. the proteins sequenced by that gene are broken down inside the cell.

Put the following steps of the convection process in the correct order. 1. gravity pulls cooler matter downward. 2. the matter expands and decreases in density. 3. an up-and-down flow of matter produces a convection current. 4. matter is heated. 5. warmed matter is forced upward. question 2 options: a) 4, 2, 5, 1, 3 b) 2, 4, 3, 1, 5 c) 3, 2, 5, 4, 1 d) 1, 4, 2, 5, 3

14. which of the following codons code for threonine? a. ucg b. ugu c. cga d. aca

How do temperature and salinity affect deepwater currents? question 15 options: as temperatures and salinity levels of water increase, the water rises to the surface where it creates currents as it moves to colder regions. they create changes in wind direction, moving denser water in the same direction as the wind and causing the deepwater circulation patterns found in the ocean. they equalize the forces on undersea currents caused by the coriolis effect as they replace more dense water with less dense water. they create density differences that cause dense deepwater currents to flow toward the equator where they displace less dense, warmer water above them.