Nokea
What is the product of the complete combustion of propane (C3H8)?
- A. CO2
- B. CO
- C. CH4
- D. C
Correct Answer: A
Rationale: The complete combustion of propane (C3H8) results in the production of carbon dioxide (CO2) and water. When a hydrocarbon such as propane undergoes complete combustion, the carbon atoms combine with oxygen to form CO2. This makes choice A, CO2, the correct answer. Choices B, C, and D are incorrect as CO is carbon monoxide, CH4 is methane, and C is elemental carbon, none of which are the primary product of the complete combustion of propane.
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Which skin condition is characterized by red, itchy, and inflamed patches?
- A. Eczema
- B. Psoriasis
- C. Melanoma
- D. Keloid
Correct Answer: A
Rationale: Eczema is a skin condition characterized by red, itchy, and inflamed patches. It is a common condition that can vary in severity and often presents with symptoms such as dry, scaly skin, and sometimes oozing or crusting. Psoriasis, on the other hand, presents with red, scaly patches but is not typically described as itchy. Melanoma is a type of skin cancer characterized by the development of abnormal moles, while keloid is a type of raised scar that can occur after an injury to the skin. Therefore, the correct answer is eczema due to its specific symptom presentation of red, itchy, and inflamed patches.
Which of these is NOT a function of the large intestine?
- A. Absorbing water and electrolytes
- B. Producing vitamins
- C. Breaking down fiber
- D. Eliminating waste products
Correct Answer: B
Rationale: A) Absorbing water and electrolytes: The large intestine plays a crucial role in absorbing water and electrolytes from the indigestible food matter that passes through it. This helps in maintaining the body's fluid balance and preventing dehydration. B) Producing vitamins: While the large intestine contains bacteria that can produce some vitamins like vitamin K and certain B vitamins, the primary site for vitamin production is the small intestine and other organs like the liver. Therefore, producing vitamins is not a primary function of the large intestine. C) Breaking down fiber: The large intestine is responsible for breaking down fiber that was not digested in the small intestine. The bacteria in the large intestine ferment fiber, producing short-chain fatty acids that can be used as an energy source by the body. D) Eliminating waste products: One of the main functions of the large intestine is to eliminate waste products, including indigestible food matter, dead cells, and bacteria, from the body in the form of feces. Therefore, the correct answer is B, as producing vitamins is not a primary function of the large intestine.
What element has the atomic number 17?
- A. Chlorine (Cl)
- B. Nitrogen (N)
- C. Sodium (Na)
- D. Fluorine (F)
Correct Answer: A
Rationale: The correct answer is Chlorine (Cl). The atomic number of an element corresponds to the number of protons in its nucleus. Chlorine has an atomic number of 17, indicating it has 17 protons. Therefore, the element with atomic number 17 is Chlorine (Cl). Choice B, Nitrogen (N), has an atomic number of 7, Choice C, Sodium (Na), has an atomic number of 11, and Choice D, Fluorine (F), has an atomic number of 9. These elements do not match the atomic number 17, making them incorrect choices.
How is power related to work and time?
- A. Power = Work · Time
- B. Power = Work Time
- C. Power = Work + Time
- D. Power = Work - Time
Correct Answer: A
Rationale: Power is defined as the rate at which work is done or the amount of work done per unit of time. The correct formula to relate power, work, and time is Power = Work · Time. This formula shows that power is calculated by dividing the amount of work done by the time taken to do that work, indicating the rate at which work is being done. Choice B (Power = Work Time) is incorrect because multiplying work and time does not yield a measure of power. Choice C (Power = Work + Time) is incorrect as adding work and time does not define power. Choice D (Power = Work - Time) is also incorrect because subtracting work and time does not relate to the concept of power.
What is the name of the regulatory region in a gene that controls its expression?
- A. Exon
- B. Intron
- C. Promoter
- D. Enhancer
Correct Answer: C
Rationale: A) Exon: Exons are the coding regions of a gene that are transcribed into mRNA and eventually translated into proteins. Exons do not regulate gene expression.
B) Intron: Introns are non-coding regions of a gene that are removed during RNA processing and do not play a direct role in controlling gene expression.
C) Promoter: The promoter is a regulatory region located at the beginning of a gene that initiates the process of transcription by binding transcription factors and RNA polymerase. It plays a crucial role in controlling gene expression.
D) Enhancer: Enhancers are regulatory regions that can be located far from the gene they regulate and can increase the transcription of a gene. While enhancers are important for gene expression, the specific region that controls gene expression is the promoter.
Therefore, the correct answer is C) Promoter, as it is the regulatory region in a gene that controls its expression by initiating transcription.