Before there was any life on earth, which gas was absent from earth's ancient atmosphere?

Name the cell structures that are needed for photosynthesis and cellular respiration

This reproductive structure can be considered an advancement over spores. It protects the embryo from injury and drying out. It also provides food for the embryo. This plant structure is a a. leaf. b. seed. c. cone. d. flower.

Replacement of damaged worn out cells is an organism can happen as a result of

What are the characteristics of divergent boundaries? Mark all that apply. A: earthquakes B: formation of new crust C: old crust sinking into the mantle only occur on the seafloor D: volcanism (This falls in Biology, right?)

What conclusions can be drawn about the action of the enzymes as the temperature increases

A nurse is assessing a client with a diagnosis of primary open-angle glaucoma. which ocular symptom should the nurse expect the client to report?

The speed of neural impulses along an axon is increased greatly by

True or false: the northern lights are caused by earth magnetic field

Which of the following is a function of the nucleus? A) stores DNA B) stores sugars C) builds proteins D) packages proteins

Animals are motile because they have: a. energy b. metabolism c. nerve and muscle fibers d. legs or wings