What does the line of red semicircles mean on a weather map? a warm front

a stationary front

a cold front

an occluded front

Which codon is the code for the amino acid histidine (his)?

Asquirrel population lives in an area. over many years, a river in that area grows wider and stronger, eventually forming a canyon. the squirrel populations on the two sides of the canyon can no longer mate with each other and ultimately form distinct species. this is an example of

Which of the following is a period in the paleozoic era? devonian cambrian permian all of the above