How many trophic levels are there in the following food chain?

grass → grasshopper → frog → snake

A. Five

B. Four

C. Three

D. Two

The movement of oxygen from an area of high concentration to an area of low concentration is an example of:

If a dam was built to block a river from flowing toward a beach, what might happen to this beach over time?

In snapdragons pink-flowered plants (RW) are produced when red-flowered (RR) plants are crossed with white-flowered (WW) plants. This type of inheritance can best be described as:

Does the perfume diffusion from high concentration to low concentration

A substance that enters into a chemical reaction is called what

Can an organ belong to more than one system? Why?

Peter is a 30-year old man whose father died of Huntington's disease. Neither Peter's mother nor a much older sister show any signs of Huntington's. What is the probability that Peter has inherited Huntington's disease?

An example of maintaining homeostasis at the system level would be

Which of the following features are NOT known to be caused by plate tectonics?

Why should a person who sells fish and fish aquaria learn about the excretory systems in animals?