Careful observers of nature realized early on that most animals have relative constant breeding population sizes. According to Dr. Colinvaux what is the major reason for that? a) Suitable breeding habitat is limiting and does not change much and therefore define the size of the breeding population
b) Even though populations grow in size after the breeding season due to the many young joining the populations, many die during the adverse season (cold winter, dry seasons, etc.)
c) Predators will keep the size of the breeding population constant by removing surplus individuals
d) Species know their "K" and will reduce the number of offspring when the population grow too much

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.

Juan and carol were studying invertebrates in biology. they knew that segmented or earth worms preferred a dark, moist habitat. during this lab, they would be investigating the responses of organisms called planaria or dugesia tigrina. these were simple flatworms that still had a one-way digestive system and a very simple nervous system. juan and carol placed the planaria in a petri dish containing cool, distilled water that was partially covered with black paper. they shined a light on the dish. next, they removed the paper and placed a small amount of chicken liver at one end of the dish. they added a few large salt crystals to the water. finally, they added drops of hot water to the cool water in the petri dish. their results can be seen in the data table. according to their experiment, all but one conclusion is valid.

Modern sea star larvae resemble some primitive vertebrate larvae. this similarity may suggest that primitive vertebrates