This question is about cicadas. If 13 year broods and 17 year broods have such different timings, how often will the gene pools actually be able to interact with one another?

compost can be added to topsoil as a:

pesticide

ecological efficiency: % of usable energy transferred as

biomass from one trophic level to the next typical is 10% efficient (90% of

energy is lost),is diagramed as the pyramid of energy flow. then osprey eagle

are tertiary consumer and the shrimp are primary consumer, so to balance

mass of shrimp (1/0.1) / 0.1 = 100 kg 

i think the answer is a.keratin is the pigment responsible for skin color.