How much of earths atmosphere is made up of nitrogen and oxygen? A. Less than 1 percent B. close to 99 percent C. 50 percent D. Between 24 and 75 percent

Explain how current and oxygen content affect the biodiversity of streams and rivers

What would happen if oxygen were not available

Which feature is characteristic of healthy coral reefs? A. Shallow, clear water B. Clear freshwater C. Deep, salty water D. Cold, murky water

3. deference between diffusion and osmosis

There are over 2,000 different enzymes in the human body. Which statement best describes why it is necessary for there to be so many different kinds of enzymes? A. Some enzymes will not react with any type of substance. B.

Which of the following is an example of convenience sampling? A) intentionally surveying a population of men about football preferences instead of women in order to focus more on the male response B) a dentist surveying patients about toothpaste

What is a cell membrane?

Which of these describes a requirement for all healthy dating relationships? O A. Making your partner jealous O B. Sexting with your partner O C. Supporting each other O D. Criticizing your partner

As part of an early experiment on the secretory system, an in vitro translation system consisting only of mRNA and ribosomes resulted in secretory proteins that were larger than the identical protein when translated in a cell. Why?

Rising sea levels are a result of a. increased amounts of precipitation. b. melting ice only. c. increased carbon dioxide levels in the water. d. melting ice and expansion of heated water.