What is a possible source of variation that created the one amino acid difference between two animals in the hemoglobin sequence?

Fossils can only be formed when? if mud, silt or tar is in the area to preserve the fossil ierosion does not occur and allows the fossil to form oxygen and microorganisms cannot decay the bones the area is dry and does not contain mud or silt

If bacteria are much too small to see, what is one reason why can we see colonies in the petri dishes that have plenty of food to eat after only a few days?

Greenthe fossil record is the history of life recorded byhuman observationgod.climatologists.remains of the past.