Nokea
What structures provide comprehensive protection for the brain?
- A. Skull
- B. Meninges (Membranes)
- C. Cerebrospinal fluid
- D. All of the above
Correct Answer: D
Rationale: The brain is a vital organ that requires robust protection, which is provided by a combination of structures. The skull acts as a hard, protective covering for the brain, shielding it from external trauma and injury. The meninges encompass three layers of membranes (dura mater, arachnoid mater, and pia mater) that envelop the brain and spinal cord, offering additional protection and cushioning. Cerebrospinal fluid, a clear, colorless fluid surrounding the brain and spinal cord, acts as a shock absorber and provides nutrients to the central nervous system. The combined function of the skull, meninges, and cerebrospinal fluid ensures comprehensive protection for the brain, making option D, 'All of the above,' the correct answer. Choices A, B, and C are not individually sufficient to provide comprehensive protection, but together, they form a multi-layered defense system for the brain.
You may also like to solve these questions
The neutral theory of molecular evolution proposes that:
- A. Most mutations in DNA are selectively neutral and do not affect an organism's fitness.
- B. All mutations are beneficial and contribute to the adaptation of a population.
- C. The rate of evolution is primarily driven by strong directional selection pressures.
- D. Genetic drift plays a negligible role in shaping genetic variation within populations.
Correct Answer: A
Rationale: Rationale:
A) The neutral theory of molecular evolution, proposed by Motoo Kimura in the 1960s, suggests that the majority of mutations that occur in DNA are selectively neutral, meaning they do not have a significant impact on an organism's fitness. These neutral mutations are not subject to natural selection and are allowed to accumulate in populations over time. This theory helps explain the high levels of genetic variation observed within populations.
B) Option B is incorrect because not all mutations are beneficial. Mutations can be neutral, harmful, or beneficial, and the neutral theory specifically focuses on the idea that many mutations are neutral in their effects.
C) Option C is incorrect because the neutral theory suggests that evolution is not primarily driven by strong directional selection pressures. Instead, it emphasizes the role of genetic drift and the accumulation of neutral mutations in shaping genetic variation.
D) Option D is incorrect because
Which gas is the most abundant in Earth's atmosphere?
- A. Nitrogen
- B. Oxygen
- C. Carbon dioxide
- D. Argon
Correct Answer: A
Rationale: Nitrogen is the most abundant gas in Earth's atmosphere, constituting approximately 78% of the air we breathe. It is essential for various biological processes, including plant growth and nitrogen fixation. Moreover, nitrogen is a key component of the greenhouse effect, playing a crucial role in regulating the planet's temperature. Oxygen, while important for respiration, comprises about 21% of the atmosphere. Carbon dioxide, though vital for photosynthesis and a greenhouse gas, is present in much lower concentrations than nitrogen. Argon, an inert gas, is a minor component of the atmosphere.
Which of the following is NOT a common location for lymph nodes?
- A. Groin
- B. Armpit
- C. Neck
- D. Liver
Correct Answer: D
Rationale: The correct answer is 'D: Liver.' The liver is not a common location for lymph nodes. Lymph nodes are small, bean-shaped structures distributed throughout the body, including common sites like the groin, armpit, and neck. They play a crucial role in the immune system by filtering lymph fluid and trapping harmful substances, aiding the body in defending against infections and diseases. The liver, on the other hand, is an organ responsible for various functions like detoxification, metabolism, and storage, but it does not house lymph nodes.
What is the primary function of nervous tissue?
- A. Movement
- B. Protection
- C. Communication and coordination
- D. Nutrient transport
Correct Answer: C
Rationale: The primary function of nervous tissue is communication and coordination within the body. Nervous tissue is composed of neurons that transmit electrical signals and supporting cells known as neuroglia. Movement is primarily controlled by the muscular system, protection is mainly provided by the skeletal system and immune system, and nutrient transport is carried out by the circulatory system. Therefore, choices A, B, and D are incorrect as they do not align with the primary function of nervous tissue.
Which type of tissue is characterized by tightly packed cells with minimal extracellular matrix and provides structural support and protection?
- A. Epithelial tissue
- B. Connective tissue
- C. Muscle tissue
- D. Nervous tissue
Correct Answer: A
Rationale: Epithelial tissue is the correct answer as it aligns with the description provided in the question. Epithelial tissue is characterized by tightly packed cells with minimal extracellular matrix, which allows it to form protective barriers on the body's surface and line internal organs, providing structural support and protection. Connective tissue, while important for support and connection between tissues and organs, does not fit the description in the question of being tightly packed with minimal extracellular matrix. Muscle tissue is responsible for movement, and nervous tissue transmits signals throughout the body, neither of which are primarily involved in providing structural support and protection as described. Therefore, based on the characteristics described in the question, epithelial tissue best fits the description of tissue that provides structural support and protection.