Nokea
What happens to the gravitational potential energy of an object as it falls freely?
- A. It decreases
- B. It increases
- C. It remains constant
- D. It becomes zero
Correct Answer: A
Rationale: The correct answer is A: 'It decreases.' When an object falls freely, its height decreases, resulting in a decrease in gravitational potential energy. The potential energy is converted into kinetic energy as the object accelerates due to gravity. This conversion process continues until the object reaches the ground or its lowest point, where the gravitational potential energy is minimal or zero. Choice B is incorrect because gravitational potential energy decreases, not increases, during free fall. Choice C is incorrect as gravitational potential energy changes due to the change in height. Choice D is incorrect as the gravitational potential energy does not instantly become zero but decreases gradually as the object falls.
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Which property of a substance remains constant regardless of changes in its shape or size?
- A. Mass
- B. Weight
- C. Volume
- D. Density
Correct Answer: A
Rationale: The correct answer is 'Mass.' Mass is a measure of the amount of matter in an object and remains constant regardless of changes in its shape or size. Weight, volume, and density can all change depending on the conditions, but mass remains the same. Weight is the force exerted on an object due to gravity, which can change based on the gravitational pull. Volume is the amount of space an object occupies, which can change if the shape or size of the object changes. Density is the mass of a substance per unit volume, which can change if either the mass or volume changes. Therefore, in this scenario, mass is the property that remains constant regardless of changes in shape or size.
Which organelle is responsible for carrying out photosynthesis in plant cells?
- A. Golgi apparatus
- B. Mitochondria
- C. Chloroplasts
- D. Lysosomes
Correct Answer: C
Rationale: A) Golgi apparatus: The Golgi apparatus is responsible for modifying, sorting, and packaging proteins for secretion or for use within the cell. It is not involved in photosynthesis.
B) Mitochondria: Mitochondria are known as the powerhouse of the cell and are responsible for generating energy in the form of ATP through cellular respiration. They are not involved in photosynthesis.
C) Chloroplasts: Chloroplasts are the organelles responsible for carrying out photosynthesis in plant cells. They contain chlorophyll, a pigment that captures light energy and converts it into chemical energy in the form of glucose.
D) Lysosomes: Lysosomes are membrane-bound organelles that contain digestive enzymes to break down waste materials and cellular debris. They are not involved in photosynthesis.
Therefore, the correct answer is C) Chloroplasts, as they are specifically responsible for carrying out photosynthesis in plant
What is the process by which a fertilized egg implants itself in the lining of the uterus?
- A. Fertilization
- B. Implantation
- C. Gestation
- D. Parturition
Correct Answer: B
Rationale: Implantation is the correct answer. It is the process where a fertilized egg attaches itself to the lining of the uterus to establish a pregnancy. Fertilization is the initial step where the sperm and egg fuse to form a zygote. Gestation refers to the period of fetal development within the uterus. Parturition is the process of giving birth and is not related to the implantation of the fertilized egg, which occurs earlier in the reproductive process.
What property of a substance refers to its ability to undergo a chemical change and form new substances with different properties?
- A. Density
- B. Mass
- C. Reactivity
- D. Volume
Correct Answer: C
Rationale: Reactivity is the property of a substance that describes its ability to undergo a chemical change and form new substances with different properties. Density (A), mass (B), and volume (D) are physical properties of a substance and do not directly relate to its ability to undergo chemical changes. Density is mass per unit volume, mass is the amount of matter in a substance, and volume is the space occupied by a substance.
Which of the following nutrients is essential for muscle growth and repair?
- A. Vitamin C
- B. Protein
- C. Carbohydrates
- D. Fat
Correct Answer: B
Rationale: Protein is essential for muscle growth and repair as it provides the necessary building blocks (amino acids) for muscle tissue synthesis and repair. While vitamins and minerals are crucial for overall health, protein has a specific role in muscle development. Carbohydrates supply energy for workouts, and fats are important for general health but are less directly involved in muscle growth and repair compared to protein.