The ground-state electron configuration for an element is \text{[Ar]}3d^74s^2[Ar]3d
7
4s
2
start text, open bracket, A, r, close bracket, end text, 3, d, start superscript, 7, end superscript, 4, s, squared
You may also see this electron configuration written as
\text{[Ar]}4s^23d^7[Ar]4s
2
3d
7
start text, open bracket, A, r, close bracket, end text, 4, s, squared, 3, d, start superscript, 7, end superscript
Which of the following is the identity of the element?

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait. 

Ascience cannot answer religious question

It is called the medulla oblongata or people usually call it medulla. it is the lower half of the brain stem continuous with the spinal cord.