Which best characterizes the Precambrian era?

A.

abundant plants and animals

B.

dinosaurs

C.

small, one-celled organisms and primitive jellyfish

D.

extensive mountain building

Where do autotrophs get energy to produce food?

Impression materials that have mechanical properties permitting considerable elastic deformation but that return to their original form are classified as:

When a virus invades a host the most common threat is

Which factor is difficult to assess in a cost-benefit analysis A. product being used by everyone B. the aesthetic value of nature identifying internal costs D. categorizing internal and external costs

You are the first aid provider on scene for a responsive person whose shirt sleeve caught fire while he was welding. The scene is safe and you have removed his burning shirt.

Why sugar dissolves easily in water but sand do not?

Independent variable (What is the variable that you deliberately change?)

Question from Campbell Biology Chapter 23: 48) If global warming permits mosquitoes to live at higher altitudes than they currently do, then in which direction should the entire plot in the correct distribution below be shifted?

What do humans and amoebas have in common

Major consequence of ozone depletion is that a. solar energy will become ineffective. b. more harmful uv rays will reach the earth's surface. c. acid rain will increase. d. certain parts of the earth will become over-vegetated.