GED Science 2

Question 1

In the winter, people like to wear coats. Why is this?

Accepted Answer

Coats decrease the loss of body heat to surroundings through insulation.

Answer

Coats work by trapping a layer of air close to the body, which acts as an insulator. This insulation significantly reduces the rate at which body heat is transferred to the colder surroundings. Therefore, coats help maintain body temperature by decreasing heat loss, rather than generating heat or increasing the temperature of the cold air itself.

Question 2

Which of the following is NOT true?

Accepted Answer

All organisms have a cell wall.

Answer

While all organisms are composed of cells and possess genetic material, not every organism has a cell wall. Animal cells, for example, lack a cell wall, having only a cell membrane. Cell walls are characteristic features of plant cells, fungi, bacteria, and some protists, providing structural support and protection.

Question 3

The polar bear's dense fur and an exceptionally thick layer of fat under its skin protect it against the freezing temperatures of the habitat. How is natural selection in the evolution of a thick coat of fur in polar bears best explained?

Accepted Answer

Polar bears with thinner fur did not survive because they were not well suited to the environment.

Answer

Natural selection dictates that individuals with traits better suited to their environment are more likely to survive and reproduce. In a freezing habitat, polar bears with thinner fur would struggle to maintain body heat, making them less likely to survive and pass on their genes. Over generations, bears with thicker fur had a survival advantage, leading to the prevalence of this trait in the population.

Question 4

Which of the following is a source of genetic variation within a species?

Accepted Answer

Mutation

Answer

Mutation is the primary source of new genetic variation within a species. These random changes in the DNA sequence can introduce new alleles and traits into a population. While other factors like natural selection act upon existing variation, mutations are responsible for creating the novel genetic material that drives evolution.

Question 5

Rainfall in a tropical region is below average for 20 consecutive years. Animals adapted for dry conditions are much more plentiful at the end of the 20 years. Which of the following statements best explains the increase in the population of these animals?

Accepted Answer

Natural selection has favored insect species with a high tolerance for dry conditions.

Answer

This scenario exemplifies natural selection, where environmental conditions favor certain traits. When a region experiences prolonged dry conditions, insect species with a high tolerance for dryness are better adapted to survive and reproduce. Over 20 years, these favored individuals pass on their genes, leading to a significant increase in their population compared to less adapted species.

GED Practice Test

GED Practice Test

GED Science 2