A strain of a cereal grain can be either dark tan, medium-dark tan, medium tan, light tan, or cream colored. When a dark tan and a cream plant are crossed, all F1 are medium tan. The F2 are distributed in a ratio of 1:4:6:4:1 from darkest to lightest. How many genes are involved in this coloration?

The correct answer is - 2 genes.

Explanation:

The number of genes involved in the coloration of the strain of cereal grain, could be either dark tan, medium-dark tan, medium tan, light tan, or cream-colored if all F1 are medium tan when crossed a dark tan crossed with cream-colored, can be calculated as follow:

suppose there are only two gene - TT dominant over tt and CC dominant over cc

then the cross would be - RRCC - rrcc

gametes - RC and rc

Cross F1: RrCc

Self cross in F2:

offspring by Punnet cross are:

RRCC  -->1/16  

RRCc,  RrCC .---> 4/16

RrCc, RRcc, rrCC--->6/16

rrCc, Rrcc--->4/16

rrcc > 1/16

thus, the correct answer is 2 genes

it has to be understood that the sea water contains a huge amount of sodium and chlorine ions and if they enter the cell of the atlantic cod fish, the cell will shrivel and the fish will die. to avoid such a condition, the fish uses active transport for the purpose of removing the ions against the gradient.

explanation:

the atlantic cod is not a maritime osmoconformer. its native application of salts is less than that of the seawater it lives in. it is continually falling water from the gills to the ocean via osmosis.

countering that, the fish is going to be swallowing seawater. but since its internal collection of salts is lower than seawater, the fish will want to go free of excess salt, and since that's going upon a gradient, then active transport, requiring energy, must be used to pump out the salt. much marine fish use the organs to filter out the salt and these fish discharge very straight urine.