What key element is no longer produced if algae is removed from the ecosphere?

5) these are organisms where the genetic material is not bound by a nucleus. they are usually unicellular.

What is thought to have caused the mass extinction at the end of the cretaceous period?

Ecologist have observed a sharp increase of sulfur dioxide in the air . what might be a possible consequence of excessive sulfur dioxide in the air ? a. acid rain b. ozone layer depletion c.ozone layer hole d.increase in sea levels