What name is given to the membranous sacs found within a chloroplast?
a) stroma
b) cristae
c) thylakoids
d) vesicles

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