An ecosystem that has a high level of is able to fill all of its niches. a. salt water b. pollution c. biodiversity d. carbon dioxide

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.

Plz genetic engineering can be applied to many fields including medicine and agriculture. which of the following is a medical application of genetic engineering? a. giving crop plants recombinant dna so that they would be resistant to herbicides. b. examining a persons pedigree to determine whether they can carry a gene for a genetic disease. c. analyzing a persons dna to see how closely they are related to another person. d. certain genes into bacteria so that they will produce a needed medicine.

To answer this question, researchers studied populations of the dusky salamander (desmognathus ochrophaeus) living on different mountain ranges in the southern appalachian mountains. the researchers tested the reproductive isolation of pairs of salamander populations by leaving one male and one female together and later checking the females for the presence of sperm. four mating combinations were tested for each pair of populations (a and b)—two within the same population (female a with male a and female b with male b) and two between populations (female a with male b and female b with male a). the proportion of successful matings for each mating combination was measured. for example, when all the matings of a particular combination were successful, the researchers gave it a value of 1; when none of the matings were successful, they gave it a value of 0. then the researchers calculated an index of reproductive isolation that ranged from 0 (no isolation) to 2 (full isolation). the reproductive isolation value for two populations is the sum of the proportion of successful matings of each type within populations (aa + bb) minus the sum of the proportion of successful matings of each type between populations (ab + ba). the table provides data for the geographic distances and reproductive isolation values for 27 pairs of dusky salamander populations.