Which of the following is NOT considered an extraembryonic membrane?
a. the yolk sac
b. the amnion
c. the chorion
d. the allantois
e. the placenta
E
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Genetic drift is the _____ in allele frequencies from generation to generation and is especially important in _____ populations
A. random change; small B. random change; large C. change due to selection; small D. change due to selection; large E. none of these
A keystone species has a greater effect on community structure than its numbers might suggest
Indicate whether the statement is true or false.
Where is the electron transport chain located in bacterial cells?
A. Mitochondrial inner membrane B. Plasma membrane C. Mitochondrial outer membrane D. Periplasm
In Drosophila, the allele red eyes (bw+) is dominant to the allele for brown eyes (bw). At another gene locus on the same chromosome, the allele for thin wing veins (hv+) is dominant to the allele for heavy wing veins (hv). Flies homozygous for bw and hv+ are crossed to flies homozygous for bw+ and hv to obtain doubly heterozygous F1 progeny.Given that these two gene loci are very closely linked, the phenotypic ratio in the F2 generation should be closest to
A. 3 red eye, thin wing veins: 1 brown eye, heavy wing veins B. 1 brown eye: 1 red eye: 1 heavy wing veins: 1 thin wing veins C. 1 brown eye, heavy wing veins: 2 red eye, thin wing veins: 1 brown eye, thin wing veins D. 1 brown eye, thin wing veins: 2 red eye, thin wing veins: 1 red eye, heavy wing veins