Nokea
Which of the following describes an experiment?
- A. The final math grades for a group of students passing through each year of elementary school are examined.
- B. The health trends of smokers in a small random sample are examined.
- C. Citizens in a local community are surveyed to determine concerns related to the next election.
- D. The effects of a new drug are tested on a group of participants.
Correct Answer: D
Rationale: Option D describes an experiment because it involves testing the effects of a new drug on a group of participants. In an experiment, researchers intentionally manipulate an independent variable (in this case, the new drug) to observe its effects on a dependent variable (the participants' health outcomes). This method allows for establishing cause-and-effect relationships between variables, which is a key characteristic of experimental research design. Choices A, B, and C do not represent experiments. Choice A involves observational analysis of math grades, choice B involves observational analysis of health trends, and choice C involves a survey, none of which involve manipulating variables to establish cause-and-effect relationships.
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Examine the following decomposition reaction: ABC → ______. Which of the following is a possible set of products for this reaction?
- A. 2AB + C
- B. AB + CD
- C. A + BC
- D. B + C
Correct Answer: C
Rationale: In a decomposition reaction, a single reactant breaks down into two or more products. For the decomposition of ABC, a plausible set of products is A + BC. This reaction represents the breakdown of ABC into two separate components: A and BC. The correct choice C aligns with the fundamental concept of decomposition reactions, where a compound disintegrates into simpler substances. Choices A, B, and D do not reflect a proper decomposition reaction as they do not demonstrate the breakdown of the original compound into distinct components.
When a certain plant is introduced into an area, and the population of a certain insect species declines, what can be concluded from this?
- A. The plant is toxic to the insect in question.
- B. The plant competes with and drives out plants that the insect feeds on.
- C. The insect population was declining anyway; the fact that it happened when the plant was introduced is a coincidence.
- D. All of these explanations may be possible; further investigation is necessary to determine which is true.
Correct Answer: D
Rationale: The given scenario presents multiple possible explanations for the decline in the insect population with the introduction of a particular plant. It could be due to the plant being toxic to the insect (Option A), competing with and driving out plants that the insect feeds on (Option B), or the decline could be coincidental with the plant introduction as the insect population was already decreasing (Option C). Without further investigation and evidence, it is not possible to definitively determine which explanation is correct. Therefore, all of these possibilities may be true, and thorough investigation is necessary to reach a conclusive conclusion.
Which of the following areas has the least amount of sweat glands?
- A. Back
- B. Palms
- C. Axilla
- D. Forehead
Correct Answer: B
Rationale: The correct answer is B - Palms. The palms have the least amount of sweat glands compared to the other options listed. The back, axilla (armpits), and forehead are all areas with a higher concentration of sweat glands in the body. The palms have fewer sweat glands to minimize water loss and maintain a better grip for activities requiring precise and controlled movement. The back, axilla, and forehead have more sweat glands to assist in thermoregulation and cooling of the body, while the palms have fewer sweat glands for functional reasons related to grip and dexterity.
Which nervous system controls voluntary motor movement?
- A. Parasympathetic
- B. Sympathetic
- C. Autonomic
- D. Somatic
Correct Answer: D
Rationale: The correct answer is D: Somatic. The somatic nervous system is responsible for controlling voluntary motor movements. It includes the motor neurons that innervate skeletal muscles and allows us to consciously control our movements. The parasympathetic and sympathetic nervous systems are part of the autonomic nervous system, which controls involuntary functions such as heart rate and digestion. Therefore, choices A, B, and C are incorrect as they are components of the autonomic nervous system and are not primarily responsible for voluntary motor movements.
Long bones are one of the five major types of bones in the human body. All of the following bones are long bones, EXCEPT
- A. Thighs
- B. Forearms
- C. Ankles
- D. Fingers
Correct Answer: D
Rationale: Long bones are one of the five major types of bones in the human body, characterized by their elongated shape. Thighs, forearms, and ankles are examples of long bones as they are longer than they are wide and have a tubular structure, aiding in support and movement. Fingers, however, are categorized as short bones due to their small size and shape. Short bones like fingers are essential for providing dexterity and precise movements rather than supporting weight or acting as levers for movement. Therefore, the correct answer is D, Fingers, as they are not classified as long bones.