What is the chemical formula for water?
H2O
CO2
NaCl
C6H12O6
Correct Answer : A
The chemical formula for water is H2O. It consists of two hydrogen atoms and one oxygen atom.
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Correct Answer is B
Explanation
In the given exothermic reaction:
CaO + H2O ⇌ Ca(OH)2 + heat
To increase the total yield of lime water (Ca(OH)â‚‚), you can apply Le Chatelier's Principle, which states that if a dynamic equilibrium is disturbed, the system will shift in a direction that counteracts the disturbance.
- A. Continuously remove Ca(OH)â‚‚: By removing the product (Ca(OH)â‚‚) as it forms, the equilibrium will shift to the right, favoring the formation of more Ca(OH)â‚‚. This is the most effective way to increase the yield.
The other options are less effective or counterproductive:
- B. Increase the temperature: Since the reaction is exothermic, increasing the temperature would shift the equilibrium to the left (toward the reactants), reducing the yield of Ca(OH)â‚‚.
- C. Increase the pressure: This reaction does not involve gases, so changing the pressure would not significantly affect the equilibrium.
- D. Add an enzyme that can catalyze this reaction: While a catalyst speeds up the rate of reaction, it does not affect the equilibrium position or the total yield of products. It simply allows the system to reach equilibrium faster.
Thus, continuously removing Ca(OH)â‚‚ is the best way to increase the total yield of lime water.
Correct Answer is A
Explanation
Transfer RNA (tRNA) is responsible for carrying amino acids to ribosomes during protein synthesis. Each tRNA molecule has a specific anticodon that matches a codon on the messenger RNA (mRNA) molecule. The tRNA molecule binds to the mRNA codon and brings the corresponding amino acid to the ribosome, where it is added to the growing polypeptide chain.
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Correct Answer is C
Explanation
Facial acne is commonly caused by the blockage and inflammation of the sebaceous glands. These glands are responsible for secreting sebum, an oily substance that helps to lubricate the skin and hair. When these glands become overactive, or their ducts are blocked by excess sebum and dead skin cells, it can lead to the formation of pimples, blackheads, or whiteheads, which are typical signs of acne.
- Sebaceous glands are found near hair follicles and are primarily responsible for acne when they become clogged.
The other options are not related to acne:
- A. Lacrimal glands: These produce tears and are associated with the eye, not the skin.
- B. Sudoriferous glands: These are sweat glands, which are involved in perspiration, not typically linked to acne.
- D. Ceruminous glands: These are found in the ear canal and produce earwax, not involved in facial skin health.
Correct Answer is A
Explanation
Innate immunity is the first line of defense against pathogens and is present at birth. It provides immediate, non-specific protection against a wide range of pathogens, including bacteria, viruses, and fungi. Innate immunity involves physical barriers, such as skin and mucous membranes, as well as cellular and molecular components, such as phagocytes and cytokines.
Adaptive immunity, on the other hand, is developed over time and provides specific protection against particular pathogens. It involves the recognition of antigens, which are specific components of pathogens, by immune cells called lymphocytes. The lymphocytes then produce antibodies that are specific to the antigens, allowing for a targeted response to the pathogen. This process takes time to develop, as the immune system needs to encounter the pathogen and mount a response.
Overall, innate immunity provides immediate, non-specific protection while adaptive immunity provides specific protection that is tailored to the particular pathogen. Both forms of immunity work together to protect the body against pathogens.
Correct Answer is C
Explanation
Spirometry is a common pulmonary function test that measures pulmonary ventilation, specifically assessing the volume and flow of air that can be inhaled and exhaled from the lungs. It provides important information about lung function and can help diagnose various respiratory conditions.
The other options do not relate to spirometry:
- A. Urinary capacity of the bladder: This is measured by urodynamics or bladder capacity tests, not spirometry.
- B. Volume of blood in the body: This can be estimated using different methods, such as dilution techniques or imaging, but not spirometry.
- D. Number of turns in the small intestine: This relates to the anatomy and function of the digestive system and is not measured by spirometry.
Thus, spirometry specifically evaluates how well the lungs are functioning in terms of air movement.
Correct Answer is D
Explanation
This reaction is exothermic (releases heat), as indicated by the presence of "Heat" on the product side (C + Heat). According to Le Chatelier's Principle, when the temperature of an exothermic reaction is increased, the equilibrium shifts to counteract the added heat by favoring the reverse reaction (where heat is absorbed).
- As a result, the system will shift towards the left (toward the reactants, A and B), to consume the excess heat.
- Therefore, the concentrations of A and B will increase, and the concentration of C will decrease.
The other options do not align with this behavior:
- A. Incorrect, as the concentration of C will change (decrease).
- B. Incorrect, the reaction will shift away from equilibrium due to the temperature change.
- C. Incorrect, the concentration of C will not increase; it will decrease.
Correct Answer is A
Explanation
The three germ layers that form during embryonic development are the ectoderm, mesoderm, and endoderm. The ectoderm is the outermost layer, and it gives rise to the skin, hair, nails, and nervous system. The nervous system develops from a specialized region of the ectoderm called the neural plate, which invaginates to form the neural tube. The neural tube ultimately gives rise to the brain and spinal cord, which make up the central nervous system, as well as the peripheral nervous system. The endoderm gives rise to the lining of the digestive and respiratory tracts, while the mesoderm gives rise to the musculoskeletal system, circulatory system, and several other organs. The exoderm is not a germ layer and does not exist during embryonic development.
Correct Answer is B
Explanation
The perineum is the region of the body located between the pubic symphysis (in the front) and the coccyx (in the back). It includes the areas surrounding the openings for the urinary, digestive, and reproductive systems, such as the urethra, anus, and, in females, the vaginal opening.
The other options describe different areas of the body:
- A. The area on the back between the neck and the two shoulder blades refers to the upper back and shoulder region, not the perineum.
- C. The area between the nipples on the chest and the belly button describes the mid-torso, not the perineum.
- D. The area between the edges of the eyes and the chin describes the face, not the perineum.
Correct Answer is D
Explanation
The unit used to indicate length is the meter (m). It is the base unit of length in the International System of Units (SI).
Correct Answer is D
Explanation
The largest organ in the human body by surface area is the skin. It covers the entire external surface of the body and has an average surface area of about 20 square feet in adults.
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