The diagram below shows the layers of a rock having a trilobite:

A rock column labeled Rock is shown. The column has three layers. The bottommost layer of the rock has one shaded rhomboid shape, the middle layer has a rhombus with a diagonal along with two identical organisms marked as, Trilobite, in the key, the top layer has two semicircles. A key is shown on the right side of the diagram. The shaded rhombus is marked as A, the rhombus with the diagonal is marked as B, the semicircle is marked as C

Which statement about the rock fossils is true?

Fossil B is older than fossil A.
Fossil A is younger than fossil C.
Fossil C belongs to the same period as the trilobite.
Fossil B belongs to the same period as the trilobite.

Many animals cannot sweat to maintain a stable body temperature. what is one other way animals can cool down?

Examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. examine the two squirrel populations in the accompanying figure. the populations are separated by a geographic barrier. if after a long period of time the two species are no longer separated, what evidence is needed to determine if speciation has occurred? the figure shows two populations of squirrels separated by a geographic barrier. polyploidy is creating new species. the two populations are not interbreeding freely. hybrid offspring of the two populations begin to appear. one species will increase into a population size twice as large as the other species.

What were the main components of earth’s earliest atmosphere? oxygen and ammonia hydrogen and helium oxygen and nitrogen hydrogen and nitrogen