A recessive gene exerts its influence only if both genes of a pair are

Genetic testing has found that Gary, Ben, Tara, and Matt all carry a copy of a gene for hemophilia. However, Tara, who is the only female out of the four, does not show any signs of the disease, whereas Gary, Ben, and Matt have developed the disease. In this scenario, it can be inferred that hemophilia is most likely a(n)

While studying a sample for height differences, researchers observed that the height of the participants varied significantly regardless of whether the participants' parents were short or tall. This suggests that the physical characteristic of height is most likely an example of

During the process of _____, a cell's nucleus—including the chromosomes—duplicates itself and the cell divides, resulting in the formation of two cells.

Which of the following is most likely to be a cause of infertility in a woman?

Carrie's parents have brown hair. However, Carrie gets genes for blond hair from both of her parents, and as a result she has blond hair. This indicates that the gene for blond hair is a

Erin, a 90-year-old, is healthy and leads an active lifestyle. Most of her relatives have lived to an old age. Researchers have found that Erin's family carries genes related to stress resistance, immunity, and metabolism that help extend life by repairing and protecting body tissues. In this scenario, which of the following genes is most likely responsible for Erin living to an old age?

The food-scarce environment of our ancestors likely led to humans' propensity to gorge when food is available and to crave high-caloric foods, a trait that might lead to an epidemic of obesity when food is plentiful. This illustrates how

Timothy is a shy 6-year-old who is usually withdrawn in class. He is always distracted in class and refuses to cooperate with other students during class activities. He does not volunteer to answer questions, and as his teachers find it difficult to elicit any response from him, they choose to ignore him. He is not liked by his classmates as he never shares his belongings. As a result, he mostly plays by himself. According to Sandra Scarr's description of the three ways that heredity and environment can be correlated, which of the following correlations is most likely exhibited in this scenario?

The _____ view states that development is the result of an ongoing, bidirectional interchange between heredity and the environment.

_____ is a stage in reproduction whereby an egg and a sperm fuse to create a single cell.

Which of the following is most likely a characteristic of persons with Klinefelter syndrome?

Benny has been diagnosed with a gene-linked abnormality characterized by deceleration of mental and physical development caused by an accumulation of lipids in the nervous system. He has been put on medication and a special diet, but his family has been told that he will probably not live beyond the age of five. Benny is suffering from

Marly describes her friend Gina as having blond hair, green eyes, and fair skin with freckles. Marly has described Gina's

Tamara, an African American, is born with a genetic disorder that causes her body's red blood cells to become hook shaped instead of being disk shaped, impairing the normal oxygen-carrying capacity of the cells. The doctors explain to Tamara's parents that this condition, however, makes her resistant to malaria. Which of the following disorders is Tamara most likely suffering from?

Charlie is a cooperative, attentive child and is a favorite at home and school; he receives positive, instructive responses from adults. This is indicative of a(n)

Samantha is diagnosed with a genetic disorder. She suffers from glandular dysfunction that hinders mucus production. She has difficulty in breathing, and her digestion is hampered. She also has frequent lung infections and suffers from shortness of breath. In this scenario, which of the following genetic disorders is Samantha most likely suffering from?

According to evolutionary developmental psychologists, many evolved psychological mechanisms are _____. That is, the mechanisms apply only to a specific aspect of a person's psychological makeup.