An egg is protected by its outer shell. However, the shell also allows moisture and air to pass through. Which cell structure performs a similar function? A. cell membrane B. cytoplasm C. nucleus D. vacuole

The greenhouse effect a. something that has occurred for millions of years b. an unnatural phenomenon caused by humans that maintains earths temperature range. c. the results of the differences in the angle of the suns rays d. an unnatural phenomenon that causes heat energy to be radiated back into the atmosphere