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Which gland produces the hormone responsible for the 'fight-or-flight' response in stressful situations?
- A. Thyroid gland
- B. Pituitary gland
- C. Adrenal gland
- D. Pancreas
Correct Answer: C
Rationale: The correct answer is C: Adrenal gland. The hormone responsible for the 'fight-or-flight' response in stressful situations is produced by the adrenal gland. This hormone is called adrenaline (epinephrine) and is released in response to stress, preparing the body to either fight the stressor or flee from it. The other choices are incorrect because the thyroid gland primarily produces hormones that regulate metabolism, the pituitary gland produces various hormones that control other endocrine glands, and the pancreas produces insulin and glucagon to regulate blood sugar levels.
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Which type of waves exhibit both longitudinal and transverse motion?
- A. Electromagnetic waves
- B. Surface waves
- C. Mechanical waves
- D. Sound waves
Correct Answer: B
Rationale: Surface waves exhibit both longitudinal and transverse motion. These waves travel along the boundary between two different mediums, such as water and air, causing particles to move both parallel (longitudinal) and perpendicular (transverse) to the wave's direction of travel. This unique characteristic distinguishes surface waves from other types of waves, making them the correct answer in this context. Electromagnetic waves, like light and radio waves, are purely transverse in nature, propagating through vacuum or different media through oscillating electric and magnetic fields perpendicular to the direction of wave travel. Mechanical waves, including both transverse (e.g., water waves) and longitudinal (e.g., sound waves in air) waves, do not typically exhibit both types of motion simultaneously, unlike surface waves.
Which kingdom primarily consists of multicellular, photosynthetic organisms with cell walls made of cellulose?
- A. Animalia
- B. Fungi
- C. Plantae
- D. Protista
Correct Answer: C
Rationale: A) Animalia consists of multicellular organisms that lack cell walls and are heterotrophic. Therefore, it does not primarily consist of photosynthetic organisms with cell walls made of cellulose. B) Fungi are multicellular organisms with cell walls made of chitin and are heterotrophic, so they do not fit the description. C) Plantae primarily consists of multicellular, photosynthetic organisms with cell walls made of cellulose. This accurately describes plants. D) Protista is a diverse kingdom that includes unicellular and multicellular organisms with varying characteristics, but it does not primarily consist of multicellular, photosynthetic organisms with cell walls made of cellulose.
What functional group is present in ethers?
- A. Hydroxyl
- B. Carbonyl
- C. Ether
- D. Amine
Correct Answer: C
Rationale: The functional group present in ethers is -O-, representing an oxygen atom bonded to two alkyl or aryl groups. Therefore, choice C, 'Ether,' is the correct answer. Choices A, B, and D refer to different functional groups: hydroxyl (-OH), carbonyl (C=O), and amine (NH2), respectively, which are not present in ethers. Ethers are characterized by the oxygen atom bonded to two carbon groups, distinguishing them from the other functional groups mentioned in the choices.
Where is the ball-and-socket joint, allowing a wide range of motion, found?
- A. Upper arm (humerus) and shoulder blade (scapula)
- B. Collarbone (clavicle) and breastbone (sternum)
- C. Two vertebrae in the spine
- D. Ribs and sternum
Correct Answer: A
Rationale: The ball-and-socket joint is located between the upper arm (humerus) and the shoulder blade (scapula). This joint provides a wide range of motion, enabling movements like flexion, extension, abduction, adduction, and rotation. It plays a crucial role in various activities involving the shoulder joint, such as throwing, reaching overhead, and performing rotational movements. Choice B, the collarbone (clavicle) and breastbone (sternum), form the sternoclavicular joint, which is a synovial saddle joint. Choice C, two vertebrae in the spine, typically form gliding or facet joints. Choice D, ribs and sternum, are connected by cartilage, forming cartilaginous joints.
What is the difference between homologous chromosomes and sister chromatids?
- A. Homologous chromosomes have the same genes but may have different alleles, while sister chromatids are identical copies of the same chromosome.
- B. Homologous chromosomes are only found in diploid cells, while sister chromatids are found in both haploid and diploid cells.
- C. Both homologous chromosomes and sister chromatids are genetically identical, but only sister chromatids separate during mitosis.
- D. Both homologous chromosomes and sister chromatids can separate during mitosis, but only homologous chromosomes have different alleles.
Correct Answer: A
Rationale: Rationale:
- Homologous chromosomes are pairs of chromosomes that have the same genes in the same order, one from each parent. While they carry the same genes, they may have different alleles (variants of a gene).
- Sister chromatids are exact copies of each other, formed during DNA replication. They are held together by a centromere and are produced during the S phase of the cell cycle.
- During meiosis, homologous chromosomes pair up and exchange genetic material through crossing over, leading to genetic variation. Sister chromatids separate during mitosis to ensure each daughter cell receives an identical copy of the genetic material.