Discuss how algae help support other life on earth?

In the distant past, algae helped turn the earth's then inhospitable atmosphere into one that could support modern life through photosynthesis, which plants use to turn carbon dioxide and sunlight into sugars and oxygen. Some of the algae sank to sea or lake beds and slowly became oil.

the cladogram shown here shows similarities and differences among several classes of vertebrates. anatomically, the four have limb structure as their common ancestor. we might separate the mammals from the other three classes because they a) divergent; do not lay eggs b) identical; are warm-blooded c) varied; a four chambered heart d) homologous; have mammary glands

whats the drop down answers ?

explanation: