Desertification is caused by a combination of converging problems, including: A. overgrazing, deforestation, drought, and climate change.
B. urban sprawl, pesticide contamination, and natural cycles.
C. contamination of irrigation water and natural cycles.
D. famine, starvation, and biodiversity loss.

Punnett squares are used to show possible combinations of alleles or to predict the probability of a trait occurring in offspring. an incomplete dominance cross is performed between a bird that is homozygous for red feathers and a bird that is homozygous for blue feathers. purple offspring result. then, two of the purple offspring are crossed. according to the punnett square for this cross, how many of the offspring from the second cross will have a feather color that results from incomplete dominance? 1 in 4 2 in 4 3 in 4 4 in 4

Natural selection changes allele frequencies because some survive and reproduce more successfully than others.

What materials must dams have to produce electricity, and what must occur?