Enzymes act as catalysts because
a. they raise the activation energy
b. they lower the activation energy
c. they use activation energy
d. they maintain activation energy

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation

Individuals do not compete directly for resources, but are prey for the same predator

In general, characteristics that an organism survive and reproduce become more common over time. what mechanism of evolution causes this?