In a different plant species from the example given, flower color is controlled by two genes that contribute equally to pigmentation in the final flower color. the more "r" alleles, the more pigmentation, such that only plants with the genotype crcr drdr have red flowers, and only plants with the genotype cwcw dwdw have white flowers. plants with three "r" alleles produce 75% as much pigmentation as crcr drdr plants and have dark pink flowers. plants with three "w" alleles produce 25% as much pigmentation as crcr drdr plants and have light pink flowers. plants with an equal number of "r" and "w" alleles produce 50% as much pigmentation as crcr drdr plants and have pink flowers. a red flowering plant was mated to a white flowering plant and all of the f1 progeny had pink flowers. these pink flowered f1 plants were allowed to self-fertilize to produce f2 progeny. what is the genotype of the f1 plants that produced pink flowers? (hint: draw punnett squares to determine the f1 and f2 genotypes and phenotypes.)

a) cwcw drdr
b) crcw drdw
c) cwcr drdr
d) crcr dwdw

Experiments in environmental toxicology can sometimes be manipulative experiments in which the researcher actively chooses and manipulates the independent variable. in hunt's study, for example, dosages of bpa were manipulated and the effects were measured. in manipulative studies, the researcher controls all the other variables in the experiment, so any health effects observed in the test subjects can be attributed to differences in the independent variable. in other cases, researchers use natural experiments in which the dependent variable (typically a measure of organism health) is measured under differing contexts that are not manipulated. say, for example, that an accidental chemical spill contaminates five ponds. to determine the possible effects of the toxic chemical on frogs, a researcher could compare the hatching rate of frog eggs laid in those five ponds to the hatching rate of eggs laid in five uncontaminated ponds nearby. this would be an example of a natural experiment because concentrations of the toxic chemical in the ponds were not controlled by the experimenter, but rather resulted from the chemical spill. drag type of experiment on the left to the example of experiment on the right. blood concentrations of bpa in college students are compared to their recent manipulative consumption of canned food items 2. the feeding behavior of fish in streams that receive acidic runoff from strip mines is compared to the feeding behavior of fish in unaffected streams. the deformity rate in baby birds from nests in pesticide-sprayed fields is compared to the deformity rate in birds from nests in unsprayed fields 4 tumor development is compared in mice exposed to five dosages of a known carcinogen in the laboratory foraging activity levels are compared in tadpoles exposed to four concentrations of toxic metals in the laboratory. growth of corn plants is compared in field plots sprayed with three different dosage: s of weed killer 7 bpa concentrations in the urine of people with diabetes are compared to bpa concentrations in the urine of people without diabetes - natural; manipulative

What occurs to the cell during mitosis

Did you know that a single bee would have to go to over 2 million flowers to make a single pound of honey?