General Science

Concept: Plants undergo two main processes: photosynthesis (daytime) and respiration (always). Photosynthesis consumes carbon dioxide and releases oxygen, while respiration consumes oxygen and releases carbon dioxide. Step 1:Understanding plant behavior during day and night.}

• Daytime: Photosynthesis Respiration. Plants release net oxygen.
• Nighttime: Photosynthesis stops (no sunlight). Only respiration occurs. Plants release carbon dioxide and consume oxygen.

Step 2:Why sleeping under a tree at night is dangerous.}
At night, trees release carbon dioxide ( ) and take in oxygen ( ). Sleeping in an enclosed or poorly ventilated area under a tree can lead to:

• Increased concentration in the surrounding air
• Reduced availability
• Headaches, dizziness, or suffocation in extreme cases

Step 3:Evaluating each option.}

• (A) release of less oxygen: Incorrect wording. The issue is not "less oxygen release" but active release of .
• (B) release of more oxygen: False. Trees do not release more oxygen at night.
• (C) release of carbon dioxide: Correct. At night, respiration dominates, releasing .
• (D) release of carbon monoxide: False. Carbon monoxide ( ) is released by incomplete combustion (vehicles, fire), not by trees.

Step 4:Conclusion.}
Sleeping under a tree at night is not advisable because trees release carbon dioxide during respiration, which can be harmful in stagnant air. The correct answer is (C).

Concept: Fermentation is the anaerobic breakdown of sugar by yeast, producing alcohol and gas. Step 1:Understand the reaction.
During fermentation:
Step 2:Identify the gas evolved.
The gas released is carbon dioxide (CO\textsubscript{2}).
Step 3:Eliminate incorrect options.}

• Oxygen Not produced in fermentation
• Carbon monoxide Not formed
• Methane Produced in anaerobic decay, not fermentation

Final Answer:

Concept: The hottest planet is determined by its surface temperature, not its distance from the Sun. Step 1:Understand why Venus is hottest.
Although Mercury is closest to the Sun, Venus has a dense atmosphere rich in carbon dioxide, causing an extreme greenhouse effect.
Step 2:Effect of greenhouse gases.
The thick atmosphere traps heat, raising surface temperatures to about:
Step 3:Eliminate incorrect options.}

• Earth Moderate temperature
• Mars Cold planet
• Jupiter Gas giant, not hottest

Final Answer:

Let's examine each of the given options to determine which one is a metal:
Carbon: Carbon is a non-metal. It exists in various allotropic forms like diamond, graphite, and fullerenes, all of which exhibit properties characteristic of non-metals.
Mercury: Mercury (Hg) is a chemical element that is a heavy, silvery-white liquid metal at standard temperature and pressure. It is unique as it is the only common metal that is liquid under these conditions.
Sulphur: Sulphur (S) is a non-metal. It is a yellow crystalline solid at room temperature and exhibits properties typical of non-metals.
Iodine: Iodine (I) is a non-metal belonging to the halogen group. It is a dark-purple solid at room temperature and sublimes to a violet gas. Based on these properties, Mercury is the only metal among the given options.

Let's match the vitamin and mineral deficiencies in List I with the diseases they cause in List II:
(A) Deficiency of Vitamin B: Deficiency of Vitamin B1 (Thiamine) causes Beri-Beri (II), a disease affecting the heart, nerves, and digestive system.
(B) Deficiency of Vitamin A: Deficiency of Vitamin A is well-known to cause Night blindness (IV), an early symptom characterized by difficulty seeing in low light conditions.
(C) Deficiency of Iron: Iron is essential for the production of hemoglobin in red blood cells. Deficiency of iron leads to Anaemia (I), a condition characterized by a reduced number of red blood cells or hemoglobin, resulting in fatigue and weakness.
(D) Deficiency of Iodine: Iodine is crucial for the proper functioning of the thyroid gland. Deficiency of iodine can lead to the enlargement of the thyroid gland, a condition known as Goitre (III). Therefore, the correct matching is: A - II B - IV C - I D - III This corresponds to option (B)

Let's match the physical quantities in List I with their corresponding units in List II:
(A) Electric charge: The SI unit of electric charge is the Coulomb (II).
(B) Force: The SI unit of force is the Newton (I).
(C) Power: Power is the rate at which energy is transferred or converted. The SI unit of power is the Watt (IV) (which is equivalent to Joule per second).
(D) Energy: Energy is the capacity to do work. The SI unit of energy is the Joule (III). Therefore, the correct matching is: A - II B - I C - IV D - III This corresponds to option (B)

Let's match the deficiencies in List I with the diseases in List II:
(A) Insulin: Insulin is a hormone that regulates blood sugar levels. A deficiency of insulin leads to Diabetes (III).
(B) Protein: Protein deficiency, especially in children, can lead to a condition called Kwashiorkor (I), characterized by edema, irritability, anorexia, and skin changes.
(C) Thyroxin: Thyroxin is a hormone produced by the thyroid gland. Its deficiency can cause Goitre (IV), an enlargement of the thyroid gland.
(D) Vitamin C: Deficiency of Vitamin C (Ascorbic acid) leads to Scurvy (II), a disease characterized by weakness, bleeding gums, and skin hemorrhages. Therefore, the correct matching is: A - III B - I C - IV D - II This corresponds to option (A)

The correct option is (A):The land themselves to scientific enquiry.