Which one of the following is the catalyst in a metabolic pathway?

a. Carbohydrates

b. Phosphate groups

c. Enzymes

Which of the following organs contains villi? esophagus stomach small intestine liver

In 1950's, Stanley Miller and Harold Urey showed how organic molecules necessary for the formation of life could be assembled from simple molecules known to have existed on Earth millions of years ago.

Where do eggs come from

How does a change in the geosphere affects the biosphere

Describe the structural organization shared by cilia and flagella.

Egg and sperm are a type of these?

Is coral a plant or an animal?

What prevents blood movement from left ventricle to left atrium

What happens in an aphotic zone of a body of water

Which of the following items would be an ecosystem within the ocean ecosystem? a. marshes b. coral reefs c. rivers d. ponds