Nokea
What is the independent variable in this experiment?
- A. Time
- B. Dog weight
- C. Dog species
- D. Dog food type
Correct Answer: D
Rationale: The independent variable is the factor that is manipulated by the researcher to observe its effects on the dependent variable. In this experiment, the researcher is likely changing the type of dog food, and this manipulation is what impacts the outcome being measured. Therefore, 'Dog food type' is the independent variable. Choices A, B, and C do not represent the variable being intentionally changed by the researcher, making them dependent variables or other factors not directly controlled or manipulated in this experiment.
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Which type of blood vessel carries blood back to the heart?
- A. Artery
- B. Vein
- C. Capillary
- D. Lymphatic vessel
Correct Answer: B
Rationale: The correct answer is B: Vein. Veins carry blood back to the heart from various parts of the body, functioning as the vessels that return blood to the heart. Arteries, on the other hand, carry blood away from the heart to different parts of the body to deliver oxygen and nutrients. Capillaries are tiny blood vessels where the exchange of gases, nutrients, and waste products occurs between the blood and tissues. Lymphatic vessels are part of the lymphatic system, responsible for maintaining fluid balance and aiding in immunity. Therefore, the correct choice is B as it directly relates to the blood flow back to the heart.
Which hormone regulates the sleep-wake cycle?
- A. Cortisol
- B. Melatonin
- C. Thyroxine
- D. Insulin
Correct Answer: B
Rationale: The correct answer is B: Melatonin. Melatonin, produced by the pineal gland, is the hormone that regulates the sleep-wake cycle. It helps signal to the body when it's time to sleep and wake up, playing a crucial role in maintaining a healthy sleep pattern. Choice A, Cortisol, is known as the stress hormone and plays a role in the body's response to stress, not specifically in regulating the sleep-wake cycle. Choice C, Thyroxine, is a hormone produced by the thyroid gland that regulates metabolism, not the sleep-wake cycle. Choice D, Insulin, is a hormone produced by the pancreas that regulates blood sugar levels, not the sleep-wake cycle.
Which of the following is part of the central nervous system?
- A. Spinal cord
- B. Peripheral nerves
- C. Brainstem
- D. Cerebellum
Correct Answer: A
Rationale: The correct answer is A: Spinal cord. The central nervous system comprises the brain and spinal cord. The spinal cord plays a crucial role in transmitting information between the brain and the body. Choices B, C, and D are not part of the central nervous system. Peripheral nerves belong to the peripheral nervous system, whereas the brainstem and cerebellum are components of the brain, distinct from the central nervous system.
Which of the following infectious diseases can be caused by a protozoan parasite?
- A. Measles
- B. Malaria
- C. Mumps
- D. Mononucleosis
Correct Answer: B
Rationale: The correct answer is B: Malaria. Malaria is caused by Plasmodium, a protozoan parasite transmitted through the bite of infected mosquitoes. Measles and mumps are viral diseases caused by separate viruses. Mononucleosis, on the other hand, is caused by the Epstein-Barr virus, which is also a viral infection. Therefore, choices A, C, and D are incorrect as they are caused by viruses, not protozoa.
Which of the following is another name for a sweat gland?
- A. Ceruminous
- B. Sebaceous
- C. Sudoriferous
- D. Integumentary
Correct Answer: C
Rationale: The correct answer is C: Sudoriferous. Sudoriferous glands are commonly known as sweat glands and are responsible for producing perspiration to regulate body temperature. Ceruminous glands produce earwax, sebaceous glands produce sebum (oil), and 'Integumentary' refers to the integumentary system, which includes the skin, hair, and nails. Choice A, Ceruminous glands, are responsible for producing earwax, not sweat. Choice B, Sebaceous glands, produce sebum (oil) to lubricate the skin and hair. Choice D, Integumentary, refers to the integumentary system, not a specific type of gland.