Nokea
Which structure is the largest part of the airway?
- A. Alveoli
- B. Bronchi
- C. Bronchioles
- D. Trachea
Correct Answer: D
Rationale: The correct answer is the trachea. The trachea is the largest part of the airway and serves as the main passageway for air to enter and exit the lungs. It connects the larynx to the bronchi and is an essential component of the respiratory system. The alveoli, although crucial for gas exchange, are tiny air sacs in the lungs and not the largest part of the airway. Bronchi and bronchioles are smaller airway passages that branch off from the trachea, making them smaller in size compared to the trachea.
You may also like to solve these questions
Which of the following is an example of a fibrous protein?
- A. Insulin
- B. Keratin
- C. Hemoglobin
- D. Collagen
Correct Answer: D
Rationale: A) Insulin is a hormone, not a fibrous protein. It is produced in the pancreas and regulates blood sugar levels.
B) Keratin is a fibrous structural protein found in hair, nails, and the outer skin layer, providing strength and protection.
C) Hemoglobin is a globular protein in red blood cells responsible for oxygen transport; it is not fibrous.
D) Collagen is a fibrous protein found in tendons, ligaments, and skin, offering strength and structure to connective tissues. Therefore, the correct answer is collagen, making it the main component of various connective tissues.
What is the basic structural and functional unit of the nervous system?
- A. Axon
- B. Neuron
- C. Dendrite
- D. Synapse
Correct Answer: B
Rationale: The correct answer is B: Neuron. Neurons are indeed the basic structural and functional units of the nervous system. Neurons are specialized cells that transmit signals throughout the nervous system, enabling communication and coordination of various functions within the body. While axons, dendrites, and synapses are all essential components of neurons and neural function, the neuron as a whole is considered the fundamental building block responsible for signal transmission. Choice A, Axon, is incorrect because an axon is a part of a neuron responsible for transmitting electrical signals away from the cell body. Choice C, Dendrite, is incorrect because dendrites are extensions of a neuron that receive signals from other neurons. Choice D, Synapse, is incorrect because a synapse is the junction between two neurons where signals are transmitted.
In a covalent bond, the shared electrons:
- A. Are completely transferred to one atom.
- B. Spend more time closer to the more electronegative atom.
- C. Remain equidistant between the two atoms.
- D. Do not influence the bond strength.
Correct Answer: B
Rationale: In a covalent bond, the shared electrons spend more time closer to the more electronegative atom. Electronegativity is the ability of an atom to attract electrons in a chemical bond. The more electronegative atom exerts a stronger pull on the shared electrons, causing them to be closer to that atom. Choice A is incorrect because in a covalent bond, electrons are shared, not completely transferred. Choice C is incorrect as the shared electrons are not equidistant but are closer to one atom due to electronegativity differences. Choice D is incorrect because shared electrons play a significant role in determining the bond strength by the strength of the bond formed through electron sharing.
Which of the following is the smallest unit of matter?
- A. Molecule
- B. Atom
- C. Compound
- D. Element
Correct Answer: B
Rationale: An atom is the fundamental building block of matter, while molecules are formed by the combination of atoms.
What is the primary source of energy entering most ecosystems?
- A. Chemical energy stored in bonds
- B. Thermal energy from the Earth's core
- C. Light energy from the sun
- D. Kinetic energy from wind and water
Correct Answer: C
Rationale: In most ecosystems, the primary source of energy is sunlight. This energy is captured by plants and other photosynthetic organisms through the process of photosynthesis. These organisms convert light energy into chemical energy stored in the bonds of organic molecules, such as glucose. This stored chemical energy is then passed on to other organisms in the ecosystem through the food chain, making sunlight the fundamental source of energy for most ecosystems. Thermal energy from the Earth's core (option B) is not a primary source of energy for ecosystems, as it is not readily accessible to most organisms. Kinetic energy from wind and water (option D) can play a role in some ecosystems, but it is not the primary source of energy. Chemical energy stored in bonds (option A) is a form of energy that is ultimately derived from the sun through photosynthesis, making it a product of the primary energy source rather than the primary source itself.