Nokea
Which gland in the endocrine system is responsible for the production of red blood cells?
- A. Pituitary gland
- B. Thyroid gland
- C. Thymus gland
- D. None of the above
Correct Answer: D
Rationale: Red blood cells are not produced by any of the glands listed in the options. Instead, red blood cells are produced in the bone marrow. The pituitary gland is known as the 'master gland' and controls several other endocrine glands but is not responsible for red blood cell production. The thyroid gland regulates metabolism and growth, not red blood cell production. The thymus gland is responsible for the production of T-cells, which are a type of white blood cell involved in the immune response. The parathyroid gland regulates calcium levels in the body, not red blood cell production. Therefore, none of the glands listed are responsible for the production of red blood cells.
You may also like to solve these questions
Which of the following describes a scalar quantity?
- A. Velocity
- B. Acceleration
- C. Force
- D. Speed
Correct Answer: D
Rationale: A scalar quantity is a physical quantity that has magnitude only, without any direction. Speed is an example of a scalar quantity because it only describes how fast an object is moving without specifying the direction of motion. Velocity, acceleration, and force are vector quantities because they have both magnitude and direction. Therefore, the correct answer is 'Speed.' Choices A, B, and C are incorrect because velocity, acceleration, and force are all vector quantities that involve both magnitude and direction.
What property of a wave remains unchanged when it passes from one medium to another with the same speed?
- A. Frequency
- B. Wavelength
- C. Amplitude
- D. Speed
Correct Answer: A
Rationale: When a wave passes from one medium to another with the same speed, its frequency remains unchanged. Frequency is a characteristic of the source of the wave and does not depend on the medium through which the wave is traveling. Wavelength and speed of the wave can change when passing from one medium to another, but frequency remains constant. This is because the frequency of a wave is determined by the source that produces it, and as long as the speed remains constant, the frequency will not be altered. Amplitude, on the other hand, can change based on factors like energy loss or gain, but it is not a property that remains constant when a wave moves between different mediums with the same speed. Speed, although important for the wave's propagation, is not the property that remains unchanged when the wave transitions between mediums with the same speed. Therefore, the correct answer is frequency.
Which of the following is NOT a mechanism of evolution?
- A. Natural selection
- B. Genetic drift
- C. Lamarckism
- D. Mutation
Correct Answer: C
Rationale: A) Natural selection is a mechanism of evolution where individuals with advantageous traits are more likely to survive and reproduce, passing on those traits to the next generation.
B) Genetic drift is a mechanism of evolution that occurs due to random changes in allele frequencies in a population.
C) Lamarckism, also known as the inheritance of acquired characteristics, is a discredited theory that suggests organisms can pass on traits acquired during their lifetime to their offspring. This mechanism has been largely rejected by the scientific community.
D) Mutation is a mechanism of evolution that introduces new genetic variation into a population, which can lead to the emergence of new traits and adaptations over time.
What is the process of converting DNA into a protein called?
- A. Transcription
- B. Translation
- C. Replication
- D. Mutation
Correct Answer: B
Rationale: Translation is the correct answer. It is the process of converting the information in mRNA into a sequence of amino acids to form a protein. Transcription (Choice A) is the process of copying a segment of DNA into RNA. Replication (Choice C) is the process of making an identical copy of DNA. Mutation (Choice D) refers to a change in the DNA sequence that can lead to variations in proteins, but it is not the process of converting DNA into a protein.
What is the difference between isometric and isotonic muscle contractions?
- A. Isometric involves movement, while isotonic does not.
- B. Isotonic involves shortening of muscle, while isometric maintains length.
- C. Isometric uses more energy, while isotonic uses less.
- D. Isotonic involves smooth muscle, while isometric involves skeletal muscle.
Correct Answer: B
Rationale: The correct answer is B. Isometric contractions occur when the muscle generates tension without changing its length, while isotonic contractions involve the muscle changing length to move a load. In isotonic contractions, the muscle shortens to move a load, whereas in isometric contractions, the muscle contracts to hold a position without movement. Choice A is incorrect because isometric contractions do not involve movement, while choice C is incorrect as isotonic contractions typically require more energy due to movement. Choice D is incorrect because the type of muscle involved (smooth or skeletal) is not the defining factor between isometric and isotonic contractions.