How long do our sleep cycles typically last during a normal night's sleep?

Which type of organism is missing from the food web seen in the illustration? primary consumers decomposers primary producers secondary consumers

Rotenone is an insecticide that is toxic

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