Why do some organisms use both types of reproduction

1. the is the thinnest part of the earth. 2. the is the thickest part of the earth. 3. what metals are mentioned in the text?

What function does the limb sever in each animal? how are the limb bones of the four animals similar? based on these similarities what can be inferred about the evolution of the four animals.

Which of the following happened during the precambrian era? the first prokaryotic cells the first eukaryotic cells development of photosynthesis all of the above