Read each example and decide what the resulting effect on the gene pool of that population would be.

1. a zebra migrates to join a different herd of zebras.
2. competition for sunlight leads to taller trees.
3. the dna of a snake changes to make its venom stronger.
4. a grassfire randomly sweeps through a population of buffalo and kills most of the animals.

then it only gives 4 options for 4 questions.

option 1. create new alleles from dna
option 2. brings new alleles from new populations
option 3. randomly selects alleles
option 4. favors certain alleles

What links the two strands in a dna helix together in the middle? a. phosphate groups b. sugar rings bonded together c. proteins d. bases with hydrogen bonds

The tasmanian devil, a marsupial carnivore, is facing extinction due to devil facial tumor disease (dftd) which causes bulging cancerous lumps and lesions to erupt around the face and neck — often causing enough deformation to make seeing or eating difficult. dftd has evolved into a contagious cancer, a trait that is unique among cancers. devil mating behavior involves biting around the head and neck, allowing cells from one individual — especially cells from the crumbly dftd tumors — to be transferred to the wounds or face of a new individual. this marsupial was once found across australia, but sea levels rose, isolating the tasmanian population, while the australian population went extinct. what would be an outcome of genetic isolation that is likely to have impacted the spread of dftd? a) reduced territory puts diseased individuals in greater contact with non-diseased ones. b) inbreeding results in less variation in facial features so the cancer is generally fatal. c) genetic isolation has made it difficult for scientists to develop a vaccine against dftd. d) the lack of genetic variation in the immune system of tasmanian devils minimizes resistance to the disease.

Modern whales developed their traits through natural selection what occurs during the process of natural selection