Given three possible phenotypes for parents showing dominance (aa, aa, aa), which combination would produce a 1: 2: 1 ratio of genotypes and a 3: 1 ratio of phenotypes?

Aa and aa will give you a 1:2:1 ratio

Aa and Aa will give you a 3:1 ratio

   a       a

A  Aa    Aa  

a  aa    aa

      A       a

A    AA     Aa

a    Aa      aa

(Give the cretit to the other person on this site: )

the correct answer is: d. the saltine and pretzel are made of flour, yeast, and baking soda, and salt. the pecan contains no flour but it does contain fats. the pecan is a nut that can be consumed as a healthy snack. first of all, pecans are a source of fat (monounsaturated fat), but they provide less fat than some other nuts. pecans are a rich source of dietary fiber, manganese magnesium, phosphorus, thiamin, vitamin e…

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!