Enzymes are catalysts because they

lower the

of a chemical

reaction

Which level of the biosphere includes both living and nonliving factors

What period did ice-age mammals first appear?

A researcher studies why frogs are disappearing in the wild. What field of biology does the research fall into?

Tropical climates are characterized by constant high temperatures at sea level with an average temperature of 18 °C or higher, and are found near the equator.

Which two species in this table are most similiar to each other?

Why is it possible for a liquid to take the shape of its container? A. Molecules of a liquid don't move at all. B. Molecules in any liquid are very far apart. C. All the particles in a liquid are round and smooth. D.

Which of the following is correctly matched with its tissue system? 1) cortex/dermal tissue system 2) cuticle/vascular tissue system 3) phloem/dermal tissue system 4) stele/vascular tissue system

Sickle cell anemia is an inherited disorder. Which of the following is a true statement about sickle cell anemia?

In a species of dogs, a black coat is dominant over a white coat. The offspring from a black dog and a white dog all have gray coats. This is an example of 1) incomplete dominance 2) complete dominance 3) codominanc 4) sex-lined genes

This is produced when the liver converts the carbon skeleton of an amino acid.