According to the cladogram in figure 18-2 what two charateristics do crabs and baracles share that limpets do not

Why is the theory of evolution important? it disproves all other theories about how life began. it provides a topic for debate. it is a unifying concept in biology. it explains how life began. i know for sure, it is not "it is a unifying concept in biology."

20 the compound al(nh3)2 has atoms of nitrogen.

Which two criteria must be met before scientist can use radiocarbon dating? explain your answer