HELP ME - The shape of songbird wings affects the efficiency of flight. Birds with more pointed wings fly long distances more efficiently, and birds with more rounded wings fly short distances more efficiently. Over the last 100 years, large portions of forests have been cut down, forcing many songbirds to travel to other forests to find mates. Which of the following evolutionary changes has most likely occurred in these bird populations as a result?
A. Bird wings are more pointed than they previously were.
B. Bird wings are more rounded than they previously were.
C. Young birds learn to use their pointed wings later than they previously did.
D. Young birds learn to use their rounded wings earlier than they previously did.

genetic variation can be caused by mutation (which can create entirely new alleles in a population), random mating, random fertilization, and recombination between homologous chromosomes during meiosis (which reshuffles alleles within an organism's offspring).

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!

it's d - life cycles - apex