Nursing Elites

1. Which of the following is unique to covalent bonds?

• A. Most covalent bonds are formed between the elements H, F, N, and O.
• B. Covalent bonds are dependent on forming dipoles.
• C. Bonding electrons are shared between two or more atoms.
• D. Molecules with covalent bonds tend to have a crystalline solid structure.

Correct answer: C

Rationale: The correct answer is C: 'Bonding electrons are shared between two or more atoms.' This statement is unique to covalent bonds. In covalent bonds, atoms share electrons to achieve a stable electron configuration, which leads to the formation of a bond. This sharing of electrons is a fundamental characteristic of covalent bonds and distinguishes them from other types of chemical bonds, such as ionic bonds, where electrons are transferred rather than shared. Choices A, B, and D do not represent unique characteristics of covalent bonds. Choice A describes some common elements involved in covalent bonds, choice B refers to the concept of dipoles, which can also exist in other types of bonds, and choice D describes a property of molecules (crystalline solid structure) that is not exclusive to covalent bonds.

2. The above experimental design description is an example of which of the following types of experiments?

• A. field experiment
• B. natural experiment
• C. controlled experiment
• D. observational study

Correct answer: C

Rationale: The above experimental design description involves the manipulation of an independent variable (light exposure) to observe its effects on the dependent variable (plant growth) under controlled conditions. In a controlled experiment, researchers actively manipulate one or more variables while keeping all other variables constant to establish cause-and-effect relationships. Choice A, a field experiment, typically takes place in a real-world setting but still involves manipulation and control of variables. Choice B, a natural experiment, involves observing naturally occurring differences in variables without researcher intervention. Choice D, an observational study, does not involve manipulation of variables, making it different from the described experimental design.

3. Which of the following is an example of a flat bone?

• A. Femur
• B. Scapula
• C. Humerus
• D. Tibia

Correct answer: B

Rationale: The correct answer is B, the Scapula. Flat bones, such as the scapula, are thin, flattened bones that provide protection to internal organs and serve as attachment points for muscles. The other choices, femur, humerus, and tibia, are examples of long bones, which are characterized by their elongated structure and are primarily involved in supporting weight and facilitating movement.

4. Which element's neutral atom has 2 electrons in the first shell and 6 electrons in the second shell of the electron cloud?

• A. Beryllium
• B. Carbon
• C. Helium
• D. Oxygen

Correct answer: D

Rationale: The correct answer is Oxygen. Oxygen has a total of 8 electrons, with 2 in the first shell and 6 in the second shell. This configuration matches the description provided in the question. Choice A, Beryllium, has 2 electrons in total, so it cannot have 2 in the first shell and 6 in the second. Choice B, Carbon, has 6 electrons in total, so it also does not match the given electron distribution. Choice C, Helium, has only 2 electrons in total and therefore does not fit the electron configuration described in the question.

5. Which hormones are responsible for stimulating the development of sex organs and secondary sex characteristics during puberty?

• A. Growth hormone
• B. Testosterone (in males) and Estrogen (in females)
• C. Insulin
• D. Thyroid hormone

Correct answer: B

Rationale: Testosterone and estrogen are the primary sex hormones responsible for the development of male and female sex organs, respectively, and the emergence of secondary sex characteristics during puberty. Growth hormone, insulin, and thyroid hormone do not directly influence the development of sex organs and secondary sex characteristics during puberty. Growth hormone primarily regulates growth and metabolism, insulin regulates blood sugar levels, and thyroid hormone controls metabolism and energy levels. Therefore, choices A, C, and D are incorrect for this question.

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