A wildlife biologist has adopted a number of techniques to protect the Willow Flycatcher, a bird that often nests and feeds in willows. Some techniques reflect top-down while some reflect bottom-up control. Which of the following approaches demonstrates her understanding of how top-down forces affect community dynamics? A. The biologist attempts to increase food availability by reintroducing beaver. She hypothesizes that beaver will raise the water table, stimulating the growth of willow, which will result in an increase in insect abundance, giving flycatchers more food.
B. Willow Fly catchers can lose eggs to squirrels, weasels, and other predators. The biologist attempts to protect nests by putting metal collars around the base of the willows that keep ground predators from climbing up to reach the nests
C. Both approaches rely on bottom-up forces.
D. Neither approach relies on bottom-up forces

Considering the yellow and green pea color phenotypes studied by gregor mendel: a. what is the biochemical function of the protein that is specified by the gene responsible for the pea color phenotype? (1 point) b. a null allele of a gene is an allele that does not specify (or encode) any of the biochemical function that the gene normally provides (in other words, either no protein at all or only non-functional protein is produced from it). of the two alleles, y and y, which is more likely to be a null allele? (1 point) c. in terms of the underlying biochemistry, why is the y allele dominant to the y allele? (2 points) d. why are peas that are yy homozygotes green? (1 point) e. the amount of protein produced from a gene is roughly proportional to the number of functional copies of the gene carried by a cell or individual. what do the phenotypes of yy homozygotes, yy heterozygotes, and yy homozygotes tell us about the amount of sgr enzyme needed to produce a yellow color? explain your reasoning. (2 points)

In order to study genetic mutations, scientists must study genetic material. which statement describes the genetic material scientists are most likely studying? a) they study alleles that contain chromosomes, which are rna.b) they study alleles that contain genes, which are chromosomes.c) they study chromosomes that contain genes, which are dna segments.

Fossils of ancestors of the modern horses show a small 4-toed almost dog-like browsing animal named eohippus over time the horses got larger lost toes and changed to a grazing diet what is the best explanation of why this change occurred