How many organisms have ever lived on Earth?

Which function of the muscular system is best illustrated by the heart pumping blood throughout the body?

Describe organisms that cannot make their own food

Which layer of the earth is mostly made of iron and nickel?

How does the liver and gallbladder aid in the digestion of your food?

The mouse is a primary consumer and a secondary consumer because it is which type of consumer? Omnivore Carnivore Herbivore Decomposer

What created the abundant agriculture in the Napa Valley of California? A:oceanic-continental convergence B: an earthquake C: a tsunami D:continental-continental convergence

Why is it difficult for most chemical reaction in living things to occur without enzyme?

Touch sensations and proprioception are carried primarily along the: a. spinocerebellar tract b. dorsal column system c. spinothalamic tract d. spinoreticular tract

What is the first step of DNA replication?

Whats not a pathogen a. virus b. dust c. fungus d. bacteria