During prenatal development, the ectoderm becomes the __________.

Correct Answer: B

Rationale: The correct answer is B: nervous system and skin. The nervous system, which includes the brain, spinal cord, and nerves, as well as the skin, develop from the ectoderm layer of cells during prenatal development. Choice A is incorrect because muscles and skeleton develop from mesoderm. Choice C is incorrect because the circulatory system and other internal organs develop from mesoderm and endoderm. Choice D is incorrect because the digestive system, lungs, urinary tract, and glands develop from endoderm.

Correct Answer: B

Rationale: In the last weeks of pregnancy, most fetuses assume an upside-down position known as the head-down position or vertex presentation. This position is ideal for a smoother labor and delivery process as it helps the baby move through the birth canal. Fetal growth has already slowed down at this stage, so option C is incorrect. Option A is inaccurate as the fetus typically gains weight in the final weeks. Option D is incorrect because the fetus relies on the mother's immune system while in the womb.

Correct Answer: C

Rationale: Rotunda, age 16, is the most likely to have had inadequate prenatal care due to her young age and possibly limited access to healthcare resources and support. Adolescents are at higher risk for inadequate prenatal care compared to older mothers due to various factors such as lack of awareness, financial constraints, and inconsistent health behaviors. Young mothers may face challenges in seeking proper prenatal care due to reasons like lack of knowledge, fear of judgment, or limited financial means. Older mothers like Lupe, Marissa, and Janette are less likely to have inadequate prenatal care compared to a younger mother like Rotunda, as they may have more access to resources, experience, and support systems.

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.

Correct Answer: A

Rationale: Naturalistic observation reflects the participants' everyday lives because it involves observing individuals in their natural environments without any manipulation. This allows researchers to see how people behave in real-world settings and can provide valuable insights into their typical behavior patterns. Choice B is incorrect because naturalistic observation focuses on observing behavior in its natural setting rather than comparing responses between participants. Choice C is incorrect as naturalistic observation tends to provide rich, qualitative data rather than a large amount of information in a short time. Choice D is incorrect because in naturalistic observation, participants are observed as they naturally behave, which may not always lead to an equal opportunity for all participants to display the behavior of interest.

Correct Answer: D

Rationale: In an experimental study examining whether the way angry encounters end affects children's emotional reactions, the dependent variable would be the children's emotional reactions. The dependent variable is the outcome being measured or tested in an experiment. In this study, the researchers are trying to understand how the way angry encounters end influences children's emotions. Therefore, the emotional reactions of the children would be the dependent variable that is being studied and measured in relation to the way angry encounters end. Choices A, B, and C are not the dependent variable in this scenario. While they may be related factors, the main focus of the study is on how the way angry encounters end impacts children's emotional reactions, making children's emotional reactions the dependent variable.

Correct Answer: C

Rationale: According to psychosexual theory, developed by Sigmund Freud, how parents manage their child's sexual and aggressive drives in the first few years is crucial for healthy personality development. This theory suggests that personality development is heavily influenced by a child's experiences during early stages of development, particularly related to handling sexual and aggressive impulses. Choices A, B, and D are incorrect as they do not align with the core principles of psychosexual theory, which focuses on the importance of early childhood experiences, especially in the context of sexual and aggressive drives.

Correct Answer: A

Rationale: Theorists who emphasize plasticity believe that change in response to influential experiences is possible. They argue that individuals have the capacity to adapt and change their behavior based on their experiences, rather than being limited by genetic predispositions or early childhood experiences. This perspective highlights the importance of environmental influences in shaping behavior and development. Choices B, C, and D are incorrect because they do not align with the concept of plasticity, which emphasizes the flexibility and adaptability of individuals in response to their experiences, rather than being fixed by heredity, childhood traits, or early experiences.

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.