The path of migration of primordial germ cells (PGCs) is an example of . In zebrafish embryos, the PGCs follow the gradient of by expressing the receptor. Fill in the blanks with the best answers.

Two true-breeding pea plants were crossed. one parent is round, terminal, violet, constricted, while the other expresses the respective contrasting phenotypes of wrinkled, axial, white, full. the four pairs of contrasting traits are controlled by four genes, each located on a separate chromosome. in the f1 only round, axial, violet, and full were expressed. in the f2, all possible combinations of these traits were expressed in ratios consistent with mendelian inheritance. (a) what conclusion about the inheritance of the traits can be drawn based on the f1 results? (b) in the f2 results, which phenotype appeared most frequently? what mathematical expression predicts the probability of occurrence of this phenotype? (c) which f2 phenotype is expected to occur least frequently? what mathematical expression predicts this probability? (d) in the f2 generation, how often is either of the p1 phenotypes likely to occur? express your answer as a fraction (example: 3/16).

Researchers determine that the biodiversity in a woodland region is declining. they identify two major threats to the region's biodiversity, a method to address each threat, and the expected outcome of each method. this information is shown in the table. threat method number of species that benefit number of years to see benefit habitat fragmentation reforestation 450 8 introduced prey species biological augmentation 150 2 which statement is an accurate explanation of the information in the table? a. biological augmentation would benefit only a few species because it is typically not very effective. b. biological augmentation would take less time to be effective because it targets the majority of prey species. c. reforestation would take the longest time to be effective because trees take several years to grow. d. reforestation would not benefit many species because most forest species live on the ground.

Creation of an unnaturally uniform sample to represent a diverse populationcan be avoided by: a. including only willing b. asking another scientist for .c. choosing only identical participants. d. selecting individuals at random.