Where is light penetration in a river or stream likely to be lowest?

a. the source

b. the mouth

c. the middle portion

d. none of the above

The hydra has an incomplete digestive system. How does the hydra remove undigested food? A. It pushes out food through an opening, which is also used to bring in food. B. It pulls food out with its tentacles. C.

Normal values for HCO3 are considered: A. 15-30 mEq/L B. 20-35 mEq/L C. 22-26 mEq/L D. 24-29 mEq/L

The EPA studies pollution and other environmental health hazards. true or false?

What are real life examples of mitosis in the human body?

All animals are eukaryotes. In a sentence or two, explain what this means.

How do scientists control the spread of disease?

What is a tetrad? A. A chromatid before meiosis B. Another term for a sperm cell C. A haploid cell produced by meiosis D. Two sets of sister chromatids

Can an organism choose how to adapt?

what are 4 human activities that interfere with ecosystems, food chains and food webs.

What process leads to water entering an aquifer? O A. Evaporation O B. Transpiration O C. Percolation O D. Condensation