Farmers often grow legumes such as soybeans every few years and plow much of the plant parts into the soil. What does this practice mainly serve?
a. to replenish the soil with useful forms of carbon
b. to replenish the soil with useful forms of nitrogen
c. to replenish the soil with useful forms of phosphorus
d. to replenish the soil with useful forms of oxygen
Ans: b. to replenish the soil with useful forms of nitrogen
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You have been asked to synthesize a new isotope for cadmium. Which part of the original atom would you need to manipulate in order to create an isotope?
A. Neutrons. B. Protons. C. Protons and neutrons. D. Electrons.
Hardy-Weinberg states out that original genotype proportions within a population remain constant across generations if certain assumptions were met. These assumptions includeA) the occurrence of random mating. (Select all that apply.)B) the lack of selection.C) the absence of polymorphic loci in the population.D) a large population size. E) an absence of gene flow.
What will be an ideal response?
Which of the following statements about the Rh marker allele is most accurate?
a. The Rh marker results from a single gene with two alleles. b. An individual's red blood cells carry the Rh cell surface marker if they have one or two copies of the dominant Rh marker allele. c. If a person has one or two copies of the dominant Rh marker allele then their blood type is noted as "positive", that is, B+ or B positive. d. If an individual has two copies of the recessive allele for the gene, they do not have any Rh markers, and are therefore are described as "negative", that is, B- or B negative. e. All of the above
African sleeping sickness is fatal if not treated because the parasite
A) evades destruction by the immune system by changing surface antigens. B) produces a toxin which binds irreversibly to neurons. C) is an intracellular parasite in RBC's, where they are not detected by the immune system. D) reproduces so fast there is no time for an immune response to develop. E) produces a non-immunogenic toxin the immune system cannot neutralize.