Why are spectral lines useful in classifying stars? A) They show the layers that make up a star.

B) They show a star's location.

C) They indicate a star's age.

D) They show the composition of a star.

Atypical human cell is approximately 12.00 μm in diameter and enclosed by a membrane that is 5.000 nm thick. (a) what is the volume of the cell including the membrane? (b) what is the volume of the cell membrane? (c) what percent of the total volume does its membrane occupy? to simplify the calculations, model the cell as a sphere. enter your answers using four significant figures.

All but one describes an effect of aging on the digestive system. a) decreased acid secretion b) decreased elasticity of stomach c) capacity to resist damage decreases d) food remains in stomach for less time

In sheep, the allele for belly fur (a) is dominant to the allele for no belly fur (a). a mother with the genotype aa and a father with the genotype aa produce an offspring.