What led to the conclusion that single-celled prokaryotic organisms evolved in the absence of oxygen

What do plants produce for animals?

Explain the role of hormones in excretion and any relation to homeostasis.

What stage of coal is most often used to heat houses and burns "cleanly"

Scientists can produce many plants in the lab by cloning; culturing a few plant cells in a test tube of chemical medium. Few cells grow into a new plant. It is easy for scientists to produce many plants from just a few cells.

A hermaphrodite is an animal with

Which factors affect a rivers load

Which sentence best captures a central idea of the biography

Is a fossil still a fossil if it is preserved artificially? For example, (Is a mummy a fossil even though it was preserved by people?)

Which type of macromolecule is the quickest source of energy for the body

Which two structures contain DNA