In primary mutant screens, A) mutant flies are identified by morphology and then the mutant genes are isolated and studied. B) mutant flies are created by RNAi using random RNA sequences and then the genes affected identified. C) mutant flies are created by gain-of-function expression of random genes. D) two mutant flies are mated to determine if there is an effect on morphology.

it is a learned trait

explanation:

answer: a) a compound microscope has a greater magnification ability than a simple microscope.

explanation:

age range would be the answer

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!