Explain why humans can be at different trophic levels on different food chains, but they can never occupy the lowest trophic level.

Which Of The Following Will Create Large Waves A. Slow Moving Wind Over A Long Period Of Time. B. A Fast Moving Puff Of Wind C. A Fast Moving Wind Over A Sustained (Long) Period Of Time D. All Of These Will Create Large Waves

What is the function of the nucleolus? A. storage of DNA B. production of tRNA C. production of mRNA D. assembly of ribosomes

According to the basic host-pathogen model, if the combined death and recovery rate from a disease doubles, and the effectiveness of the disease to spread from infected to uninfected individuals remains the same, the threshold density should A.

Which statement about sponges is NOT true? Sponges lack true tissues. Sponges actively pump water through their bodies to eat, breathe, and excrete. Sponges are filter feeders. Sponges are aquatic. Adult sponges are mobile, non-sessile animals.

An ecosystem has many levels of organization. Which level will have the most individuals? A. A population B. A biological species C. An interbreeding group D. A community

A secondary source might be eliminated by a good researcher because

Which of the following may create ethical issues to be discussed/debated in society? A. Allowing insurance companies to require DNA screens when people are applying for insurance. B.

When sunlight excites electrons in chlorophyll, what happens to them?

Why does water have a high specific heat

What energy source do plants use to produce sugar?