How much time can an egg wait the sperm to fertilize it

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

Which structure in the cardiovascular system connect arteries to veins?

The pelican's beak is adapted for in .