A mass extinction is defined as
a. the permanent loss of major groups of organisms.
b. the loss of 20% of a population.
c. the rapid growth of species diversity in a particular area.
d. the temporary loss of major groups of organisms.
e. all of these.
Answer: a. the permanent loss of major groups of organisms.
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Certain parasites, such as intestinal tapeworms, cannot survive outside of their host. Why are they still considered alive?
A. Survival outside of a host is not a requirement for life. B. As long as parasites are made of cells, they are considered to be alive. C. Parasites are still considered alive because they are studied by biologists, and biology is the study of life. D. Because they cannot survive outside of the host, parasites are actually not considered alive.
Which of the following is a protein produced by a regulatory gene?
A) operon B) inducer C) promoter D) repressor E) corepressor
Let Y = yellow and y = green, and R = round and r = wrinkled. You cross YYRR peas with yyrr peas. All of the F1 individuals are yellow and round with a genotype of YyRr. You then perform an F2 cross and get the expected 9:3:3:1 phenotypic ratio. What proportion of the F2 plants are expected to be heterozygous for both traits?
Let Cy = curly wings and Cy+ = wild type. In Drosophila, the Cy allele behaves as a dominant mutation that produces curly wings in the heterozygous condition (Cy/Cy+), but also behaves as a recessive lethal mutation. Flies homozygous for the Cy allele die before reaching adulthood. A. 1/16 B. 1/4 C. 1/2 D. 9/16 Clarify Question · What is the key concept addressed by the question? · What type of thinking is required? · What key words does the question contain? Gather Content · What do you already know about dihybrid crosses? Consider Possibilities · What other information is related to the question? Which information is most useful? Choose Answer · Given what you now know, what information and/or problem solving approach is most likely to produce the correct answer? Reflect on Process · Did your problem-solving process lead you to the correct answer? If not, where did the process break down or lead you astray? How can you revise your approach to produce a more desirable result?
Treponema pallidum is similar in shape to
A. Escherichia coli. B. Staphylococcus aureus. C. Leptospira interrogans. D. herpes virus.