Polyploidy is a condition in which organisms have extra sets of chromosomes. Scientists have observed many examples of polyploidy in plants, including crop plants such as bananas, limes, and strawberries. What best describes polyploidy in these plants?

Sea levels are rising due to climate change while increasing numbers of people are moving into coastal areas. to accommodate more people, there has been increased construction of beachfront resorts and condominiums. how is this impacting sea turtle numbers and biodiversity and why? a. the increased human population in coastal areas has meant that more food is available to the turtles (e. g., dropped food, waste from restaurants), which has led to an increase in the numbers and diversity of sea turtles. b. there has been very little change in the numbers and biodiversity of sea turtles because the planet is so vast that they can simply relocate to less crowded beaches. c. this has resulted in a decrease in numbers and diversity of sea turtles because it is restricting available nesting sites, and hence reproduction. d. this has resulted in an increase in numbers and diversity of sea turtles because people are around to protect them from natural predators.

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

Select the true statements about eubacteria. most live as decomposers and heterotrophs. most only thrive in a narrow range of environments. certain eubacteria are responsible for food poisoning. eubacteria thrive in extreme environments.