Nokea
Why is an extensive network of blood vessels necessary to supply the endocrine glands?
- A. To filter waste from the blood
- B. Because the glands empty directly into the blood
- C. To allow blood to empty into the endocrine system
- D. To filter waste from the endocrine glands
Correct Answer: B
Rationale: The correct answer is B. Endocrine glands release hormones directly into the blood, which is why they require a rich blood supply to ensure effective hormone distribution throughout the body. The extensive network of blood vessels allows hormones to be quickly transported to target tissues and organs, regulating various physiological functions. Choices A, C, and D are incorrect because endocrine glands do not filter waste from the blood or the glands themselves. They release hormones into the bloodstream to regulate bodily functions, making a direct connection to the blood supply crucial for their function.
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What is a benefit of a taxonomic system?
- A. Researchers can describe how living things behave.
- B. Researchers can develop names for new organisms.
- C. Living things can be distinguished from nonliving things.
- D. Living things can be classified based on their molecular traits.
Correct Answer: D
Rationale: The correct answer is D. A taxonomic system allows scientists to classify living organisms based on their molecular and genetic traits. This classification helps in understanding the relationships and evolutionary history of different organisms, providing insights into their characteristics and behaviors. Choices A, B, and C do not directly relate to the primary purpose and benefit of a taxonomic system, which is the systematic classification of organisms.
Which of the following is a characteristic of an interneuron?
- A. Forms neural circuits
- B. Interacts with effectors
- C. Sends impulses to the CNS
- D. Functions as an efferent nerve cell
Correct Answer: A
Rationale: The correct characteristic of an interneuron is that it forms neural circuits, connecting sensory and motor neurons within the central nervous system. Interneurons facilitate communication between different neurons in the central nervous system, helping in the processing and integration of signals. Choice B is incorrect as interneurons primarily interact with other neurons, not effectors. Choice C is incorrect as interneurons typically do not send impulses to the CNS; they operate within the CNS. Choice D is incorrect as interneurons are not efferent nerve cells; they are mainly involved in processing signals within the CNS rather than transmitting signals to effectors.
Which part of the hair is not attached to the follicle?
- A. Bulb
- B. Root
- C. Shaft
- D. Strand
Correct Answer: C
Rationale: The correct answer is C, 'Shaft.' The hair shaft is the part of the hair that extends above the skin surface and is not attached to the follicle. The bulb and root are parts that are connected to the follicle as they are located below the skin surface and play a role in hair growth. The strand, on the other hand, refers to a single hair fiber and is not a distinct part of the hair anatomy.
A person wakes up with a fever. The body begins its response to locate the origin of the problem and fix it. What type of feedback mechanism is this?
- A. Equal
- B. Negative
- C. Neutral
- D. Positive
Correct Answer: B
Rationale: This scenario describes a negative feedback mechanism. When the body detects a fever, it initiates responses to lower the temperature back to normal levels. Negative feedback mechanisms work to counteract changes and maintain homeostasis in the body. Choice A ('Equal') is incorrect as feedback mechanisms aim to restore balance, not maintain an equal state. Choice C ('Neutral') is incorrect as it does not describe the corrective nature of negative feedback. Choice D ('Positive') is incorrect as it would amplify the fever rather than regulate it.
During which phase of meiosis do chiasmata structures form?
- A. Prophase I
- B. Prophase II
- C. Metaphase I
- D. Metaphase II
Correct Answer: A
Rationale: Chiasmata structures, where crossing over occurs, form during Prophase I of meiosis. This phase is characterized by homologous chromosomes pairing up and crossing over, leading to the exchange of genetic material between non-sister chromatids. Chiasmata are visible points of contact where genetic material has been exchanged, and they play a critical role in genetic diversity. Prophase II is the phase where chromosomes condense again in the second meiotic division, but chiasmata formation occurs in Prophase I. Metaphase I is the phase where homologous chromosomes align at the metaphase plate, not where chiasmata form. Metaphase II is the phase where replicated chromosomes align at the metaphase plate in the second meiotic division, but chiasmata formation occurs earlier in Prophase I.