Diversifying selection typically results in a population with only one allele. purifying selection best describes the removal of deleterious alleles. stabilizing selection increases genetic variation within a population. balancing selection typically increases the frequency of one allele while decreasing the frequency of others. directional selection occurs when heterozygotes are more fit than either homozygous genotype.

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 

answer: substrate concentration. enzymes work best when there is a high enough substrate concentration for the reaction they catalyse.