Correct Answer: A

Rationale: The correct answer is A: 5 to 10 minutes. The third stage of labor typically lasts about 5 to 10 minutes. This stage begins after the baby is born and ends when the placenta is delivered. It is the shortest stage of labor compared to the first and second stages. Choice B, 20 to 50 minutes, is incorrect as it is too long for the duration of the third stage. Choice C, 4 to 6 hours, and Choice D, 12 to 14 hours, are also incorrect as they are significantly longer than the actual duration of the third stage of labor.

Correct Answer: C

Rationale: The recommended weight gain during pregnancy depends on the pre-pregnancy weight of the mother. For a woman with a normal pre-pregnancy BMI, the recommended weight gain is typically between 25 to 30 pounds. This range is considered healthy to support the growth and development of the baby while also maintaining the mother's health. Choices A, B, and D are incorrect as they represent weight gain ranges that are either too low or too high for a woman with a normal pre-pregnancy BMI, which could pose health risks for both the mother and the baby. It is crucial to adhere to healthcare professionals' guidelines to ensure a healthy pregnancy and birth outcome.

Correct Answer: A

Rationale: The correct answer is A: 5 to 10 minutes. The third stage of labor typically lasts about 5 to 10 minutes. This stage begins after the baby is born and ends when the placenta is delivered. It is the shortest stage of labor compared to the first and second stages. Choice B, 20 to 50 minutes, is incorrect as it is too long for the duration of the third stage. Choice C, 4 to 6 hours, and Choice D, 12 to 14 hours, are also incorrect as they are significantly longer than the actual duration of the third stage of labor.

Correct Answer: A

Rationale: Men with even tiny amounts of dioxin in their bloodstream father nearly twice as many girls as boys. This is due to the impact of dioxin exposure on sperm cells, leading to a skewed ratio of female to male offspring. Choice B is incorrect as the question specifically mentions that men father more girls than boys. Choice C is incorrect as dioxin exposure does not necessarily lead to more twins and triplets. Choice D is incorrect as men with dioxin in their bloodstream father more girls, not fewer children overall.

Correct Answer: C

Rationale: A case study would be the best method for Dr. Bigelow to study musical prodigies. In a case study, the researcher can closely examine and analyze the unique characteristics, abilities, and behaviors of individual subjects. This method allows for in-depth exploration of a specific phenomenon, making it ideal for investigating exceptional cases such as musical prodigies. Naturalistic observation involves observing subjects in their natural environment without interference, which may not provide the detailed insights needed for studying musical prodigies. Clinical interviews focus on gathering information through structured questioning, not ideal for studying unique talents. Structured interviews involve asking a set of predetermined questions, which may not allow for the depth of exploration required for studying musical prodigies.