Q: The sex of a child before birth can be determined by:

A: Amnoscopy

B: Amniocentesis

C: Amniograpghy

D: None of these



Correct Option: B  [ Amniocentesis ]

Remark:

Explanation: Amniocentesis is a medical diagnostic procedure used to determine the genetic and chromosomal makeup of a developing fetus. It involves the withdrawal of a small amount of amniotic fluid from the uterus using a fine needle. This fluid contains fetal cells that can be tested to identify genetic disorders such as Down’s syndrome and also to determine the sex of the fetus. However, using amniocentesis for sex determination is illegal in India under the Pre-Conception and Pre-Natal Diagnostic Techniques (PCPNDT) Act to prevent female foeticide.


Q: Which one of the following gases, present in the air near the surface of the Earth, has maximum concentrations?

A: Oxygen

B: Hydrogen

C: Nitrogen

D: Methane



Correct Option: C  [ Nitrogen ]

Remark:


Q: Which one is a water soluble vitamin?

A: Vitamin A

B: Vitamin C

C: Vitamin K

D: Vitamin D



Correct Option: B  [ Vitamin C ]

Remark:

Explanation: Vitamins are classified into two categories based on their solubility — fat-soluble and water-soluble. Vitamin C (ascorbic acid) and the B-complex vitamins are water-soluble, meaning they dissolve in water and are not stored in the body. Therefore, they must be consumed regularly through diet. Deficiency of Vitamin C causes scurvy, characterized by bleeding gums and delayed wound healing.


Q: Acid rain is caused due to the pollution of environment by:

A: Carbondioxide and Nitrogen

B: Carbon monoxide and Carbondioxide

C: Ozone and Methane

D: Some oxide of Nitrogen and Sulpher



Correct Option: D  [ Some oxide of Nitrogen and Sulpher ]

Remark:

Explanation: Acid rain is caused by the presence of sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) in the atmosphere. These gases are mainly released from the burning of coal, petroleum, and other fossil fuels in industries and vehicles. When they combine with water vapor and oxygen in the air, they form sulphuric acid (H₂SO₄) and nitric acid (HNO₃). These acids mix with rainwater and fall as acid rain, which damages soil, crops, aquatic life, and even monuments like the Taj Mahal.


Q: The largest artery in human body is:

A: Aorta

B: Capillary

C: Vena cava

D: Pulmonary vein



Correct Option: A  [ Aorta ]

Remark:

The aorta is the largest artery in the human body. It originates from the left ventricle of the heart and distributes oxygenated blood to all parts of the body through its various branches. The aorta has thick, elastic walls that can withstand the high pressure of blood pumped directly from the heart. It is divided into parts such as the ascending aorta, aortic arch, and descending aorta.

Other options (for context)

  • Capillary: The smallest blood vessels where exchange of gases and nutrients occurs.
  • Vena cava: The largest vein, not an artery; it carries deoxygenated blood back to the heart.
  • Pulmonary vein: Carries oxygenated blood from the lungs to the heart but is not the largest vessel.


Q: The longest cell in animals is

A: Nerve cell

B: Hepatocyte (Liver cell)

C: Blood cell

D: Muscle cell



Correct Option: A  [ Nerve cell ]

Remark:

Explanation: The nerve cell or neuron is the longest cell in animals. It consists of a cell body, dendrites, and a long fiber called the axon. In humans, the axon of a motor neuron can be over 1 meter long (from the spinal cord to the toes). This structure helps transmit electrical impulses rapidly across the body, allowing coordination and communication between organs.


Q: Chemical name of 'Baking powder' is :

A: Ammonium Chloride

B: Magnesium Phosphate

C: Sodium bi-carbonate

D: Ammonium bi-phosphate



Correct Option: C  [ Sodium bi-carbonate ]

Remark:

Explanation: The chemical name of baking powder is sodium bicarbonate (NaHCO₃), also known as baking soda. It is a mild alkali used in cooking and baking as a leavening agent. When heated or mixed with an acid (like vinegar, lemon juice, or cream of tartar), it decomposes to release carbon dioxide gas (CO₂). The bubbles of CO₂ make the dough rise and become soft and spongy. In commercial baking powder, sodium bicarbonate is often mixed with a weak acid and a drying agent.


Q: If we add salt to pure water, its boiling point will

A: increase

B: decrease

C: remains same

D: None of the above



Correct Option: A  [ increase ]

Remark:

Explanation: When salt is added to pure water, its boiling point increases. This phenomenon is known as boiling point elevation, a colligative property. The presence of dissolved salt particles reduces the vapor pressure of water, requiring a higher temperature for it to boil.


Q: Persistence of vision is the principle behind:

A: Camera

B: Binocular

C: Cinema

D: Periscope



Correct Option: C  [ Cinema ]

Remark:


Q: Which of the following is used in pencils ?

A: Graphite

B: Silicon

C: Charcoal

D: Phosphorous



Correct Option: A  [ Graphite ]

Remark:

Graphite is used in pencils. It is a soft form of carbon that leaves a dark mark on paper due to its layered structure, where carbon atoms are arranged in sheets that slide easily over each other. Though commonly called “lead,” pencils actually contain graphite mixed with clay to adjust hardness.

  • Silicon: Used in electronics, not pencils.
  • Charcoal: Used in art drawing but not regular pencils.
  • Phosphorous: Used in safety matches and fertilizers, not pencils.
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