In the food chain: Grass → Cricket → Frog → Snake → Hawk, which organism is a tertiary consumer?

In a food chain, which organism is the primary consumer?
For AA × aa, what is the genotype of all offspring?

In the food web below, what would happen if all the frogs were removed?

Natural selection can BEST be described as:

In an energy pyramid, which level has the MOST energy?
Use the Punnett square to determine the probability of offspring with the homozygous recessive (aa) genotype.

Which of the following is a biotic factor?
Which process in the water cycle is shown by arrow X?

The relationship between a bee and a flower is an example of: