Nokea
What is the term for the balanced equation that represents a chemical reaction?
- A. Hypothesis
- B. Chemical formula
- C. Balanced equation
- D. Reaction mechanism
Correct Answer: C
Rationale: The correct answer is C - 'Balanced equation'. A balanced equation is a representation of a chemical reaction that shows the reactants, products, and their stoichiometric coefficients. It ensures that the number of atoms of each element is equal on both sides of the equation, following the law of conservation of mass. Choice A, 'Hypothesis', is incorrect as it refers to a proposed explanation based on limited evidence as a starting point for further investigation. Choice B, 'Chemical formula', is incorrect as it represents the composition of a compound using symbols and subscripts. Choice D, 'Reaction mechanism', is incorrect as it describes the step-by-step process by which a chemical reaction occurs, not just the overall representation of the reaction itself.
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Which type of symbiosis benefits both organisms from the interaction?
- A. Mutualism
- B. Commensalism
- C. Parasitism
- D. Predation
Correct Answer: A
Rationale: The correct answer is 'Mutualism.' Mutualism is a type of symbiosis where both organisms involved benefit from the interaction. This relationship is characterized by cooperation and mutual support, leading to advantages for both parties. In mutualistic relationships, each organism provides something that the other needs, resulting in a mutually beneficial outcome. In contrast, 'Commensalism' (choice B) involves one organism benefiting while the other is unaffected, 'Parasitism' (choice C) benefits one organism at the expense of the other, and 'Predation' (choice D) benefits the predator while harming the prey. Examples of mutualism include the relationship between bees and flowers (pollination) and the partnership between nitrogen-fixing bacteria and leguminous plants.
Which of the following minerals is important for bone health and is stored in bones by the skeletal system?
- A. Iron
- B. Sodium
- C. Calcium
- D. Magnesium
Correct Answer: C
Rationale: The correct answer is Calcium (Choice C). Calcium is essential for bone health and is stored in bones by the skeletal system. Bones act as a reservoir for calcium, playing a critical role in maintaining bone strength and density. Iron, sodium, and magnesium are important for various bodily functions but are not primarily stored in bones for bone health. Iron is crucial for oxygen transport, sodium helps regulate fluid balance, and magnesium is involved in over 300 enzymatic reactions in the body.
What type of energy does an object in motion possess?
- A. Potential energy
- B. Kinetic energy
- C. Thermal energy
- D. Chemical energy
Correct Answer: B
Rationale: The correct answer is B. Kinetic energy is the energy possessed by an object in motion. When an object is in motion, it has the ability to do work due to its motion, which is known as kinetic energy. Potential energy, choice A, refers to stored energy that has the potential to do work but is not related to motion. Thermal energy, choice C, is related to the temperature of an object, not its motion. Chemical energy, choice D, is energy stored in the bonds of chemical compounds and is not directly related to an object's motion.
What is the difference between type 1 and type 2 diabetes, both related to insulin and blood sugar?
- A. Type 1 is caused by insulin resistance, type 2 by insulin deficiency.
- B. Type 1 is temporary, type 2 is permanent.
- C. Type 1 affects adults, type 2 affects children.
- D. Type 1 is treated with diet only, type 2 requires medication.
Correct Answer: A
Rationale: The correct difference between type 1 and type 2 diabetes lies in their underlying causes. Type 1 diabetes is caused by the body's inability to produce insulin, while type 2 diabetes is characterized by insulin resistance, where the body doesn't effectively use the insulin it produces. Insulin resistance is a key feature of type 2 diabetes, distinguishing it from type 1 where insulin deficiency is the primary issue. Choices B, C, and D are incorrect. Type 1 and type 2 diabetes can both be chronic conditions, affecting individuals of different age groups, and typically require a combination of diet, exercise, and medication for management.
A rocket engine expels hot gases backwards. What principle explains the rocket's forward motion?
- A. Newton's first law of motion
- B. Newton's second law of motion
- C. Newton's third law of motion
- D. Law of conservation of energy
Correct Answer: C
Rationale: Newton's third law of motion states that for every action, there is an equal and opposite reaction. In the case of a rocket engine expelling hot gases backwards, the action is the expulsion of gases, and the reaction is the forward motion of the rocket. The hot gases being expelled act as the action force, propelling the rocket in the opposite direction as the reaction force, resulting in the rocket's forward motion. Newton's first law of motion (Choice A) pertains to inertia, stating that an object in motion will stay in motion unless acted upon by an external force. Newton's second law of motion (Choice B) relates force, mass, and acceleration, which is not directly applicable to the scenario of a rocket engine propulsion. The law of conservation of energy (Choice D) is a fundamental principle stating that energy cannot be created or destroyed but can only be transformed, which does not directly explain the forward motion of the rocket in this context.