Nokea
Which of the following is a characteristic of unsaturated fatty acids?
- A. They are solid at room temperature.
- B. They contain only single bonds.
- C. They have a higher melting point.
- D. They contain double or triple bonds.
Correct Answer: D
Rationale: The correct answer is D. Unsaturated fatty acids are characterized by the presence of double or triple bonds in their carbon chain. These bonds introduce kinks in the chain, preventing tight packing, and resulting in a lower melting point compared to saturated fatty acids. Choice A is incorrect because unsaturated fatty acids are typically liquid at room temperature due to their kinked structure. Choice B is incorrect because unsaturated fatty acids contain double or triple bonds, not only single bonds. Choice C is incorrect as unsaturated fatty acids have a lower melting point compared to saturated fatty acids.
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Which bones are included in the axial skeleton?
- A. Head, neck, and trunk
- B. Arms and legs
- C. Hands and feet
- D. All of the above
Correct Answer: A
Rationale: The correct answer is A: Head, neck, and trunk. The axial skeleton comprises bones located in the head, neck, and trunk region, such as the skull, vertebral column, and rib cage. These bones provide structural support and protect vital organs like the brain, spinal cord, and heart. Choices B and C are incorrect because arms, legs, hands, and feet are part of the appendicular skeleton, not the axial skeleton. The appendicular skeleton is responsible for movement, manipulation, and mobility, while the axial skeleton primarily provides central support and protection for essential organs.
Define the term 'velocity' in relation to motion.
- A. Speed in a specific direction
- B. Distance traveled in a given time
- C. Rate of change of position
- D. Acceleration due to gravity
Correct Answer: A
Rationale: Velocity is a vector quantity that describes the speed of an object along with its direction of motion. Unlike speed, which is a scalar quantity focusing solely on the magnitude of motion, velocity considers both speed and direction. Therefore, the best definition of velocity is 'speed in a specific direction.' Choice B, 'Distance traveled in a given time,' is incorrect as it defines speed rather than velocity. Choice C, 'Rate of change of position,' is more aligned with the definition of velocity but lacks the specificity of direction. Choice D, 'Acceleration due to gravity,' is unrelated to the definition of velocity and refers to a different concept in physics.
When ethanol (Câ‚‚Hâ‚…OH) reacts with sodium metal (Na), what is the product?
- A. Ethene (Câ‚‚Hâ‚„)
- B. Sodium ethoxide (Câ‚‚Hâ‚…ONa)
- C. Ethane (C₂H₆)
- D. Sodium acetate (CH₃COONa)
Correct Answer: B
Rationale: When ethanol (C₂H₅OH) reacts with sodium metal (Na), the product formed is Sodium ethoxide (C₂H₅ONa). This reaction is a classic example of a metal displacing hydrogen in an alcohol to form an alkoxide. In this specific case, sodium replaces the hydrogen in ethanol, resulting in the formation of sodium ethoxide. Choice A, Ethene (C₂H₄), is incorrect as it is a different compound formed from the dehydration of ethanol, not its reaction with sodium. Choice C, Ethane (C₂H₆), is incorrect as it is a saturated hydrocarbon, not the product of the reaction of ethanol with sodium metal. Choice D, Sodium acetate (CH₃COONa), is incorrect as it involves acetic acid, not ethanol, reacting with sodium to form the salt sodium acetate.
What is the process by which one element changes into another through radioactive decay known as?
- A. Transmutation
- B. Fission
- C. Fusion
- D. Oxidation
Correct Answer: A
Rationale: The correct answer is A: Transmutation. Transmutation is the correct term to describe the process by which one element changes into another element through radioactive decay. In transmutation, the atomic structure of the element is altered, leading to a change in the element's identity. Choice B, Fission, refers to the splitting of a heavy nucleus into lighter nuclei. Choice C, Fusion, involves the merging of lighter nuclei to form a heavier nucleus. Choice D, Oxidation, is not related to the process of one element changing into another through radioactive decay.
Which of the following organs is responsible for the mechanical breakdown of food into smaller pieces?
- A. Esophagus
- B. Stomach
- C. Small intestine
- D. Mouth
Correct Answer: D
Rationale: The correct answer is D: Mouth. The mouth is responsible for the mechanical breakdown of food through chewing and mixing with saliva. This process is essential for breaking down food into smaller, more digestible pieces before swallowing. The esophagus (choice A) is a muscular tube that transports food from the mouth to the stomach and does not participate in the mechanical breakdown of food. The stomach (choice B) primarily functions to further break down food using acids and enzymes, rather than mechanical means. The small intestine (choice C) is responsible for absorbing nutrients from the digested food, not for the mechanical breakdown of food.