Multiple-Choice Questions

Noise pollution

Reason — Living close to an airport exposes Rita to constant noise from airplanes taking off and landing, which can lead to noise pollution. Prolonged exposure to high levels of noise can cause stress, increase blood pressure, and result in headaches.

Pancreas

Reason — The pancreas is an exo-endocrine gland because it has both exocrine and endocrine functions. It secretes digestive enzymes into the small intestine via ducts (exocrine activity) and produces hormones like insulin and glucagon, which are released directly into the bloodstream to regulate blood sugar levels (endocrine activity).

Both A and R are true.

Reason — Dialysis is a medical process used to remove waste products like urea from the blood when the kidneys are not functioning properly. Urea is a waste product produced in the body and its accumulation can lead to toxicity if not removed.

Colour blindness

Reason — Colour blindness is genetic medical condition in which the patient is not able to differentiate between the colours.

Plasmolysis

Reason — The salt makes the soil solution hypertonic. When cells come in contact with the soil solution, the cell sap comes out by exosmosis resulting in shrinkage of cell known as plasmolysis. Plasmolysis cause wilting of plant.

poisoning by the accumulation of high quantities of urea in the body.

Reason — Due to vomiting and watery bowels, the intestine are unable to absorb water into the blood. Therefore, to maintain the osmotic pressure of blood kidneys reabsorb almost all the water along with urea. This further causes poisoning by the accumulation of high quantities of urea in the body.

metaphase, anaphase

Reason — During metaphase, the chromosomes align themselves along the equatorial plane of the cell, called the metaphase plate. In anaphase, the sister chromatids of each chromosome are pulled apart by the spindle fibers towards the opposite poles of the cell. The centromeres split, and the chromatids (now individual chromosomes) move away from the center.

equal to that of blood.

Reason — In dialysis, the osmotic pressure of the dialysis fluid should be equal to that of blood to prevent excessive movement of water either into or out of the blood. This ensures that waste products like urea and excess salts are removed without causing an imbalance in fluid levels or electrolytes in the body.

At the time of the stress, fewer hormones are released into the blood.

Reason — In a stressful situation, more hormones, including adrenaline and other stress-related hormones, are released into the bloodstream to help the body cope with the stress.

A is False, and R is true

Reason — The pulmonary artery does not pump oxygenated blood. In fact, it pumps deoxygenated blood from the right ventricle to the lungs for oxygenation. After oxygenation, the oxygenated blood returns to the heart through the pulmonary veins.

ii and iii

Reason — Quick closing of the eyelids when a strong beam of light is flashed across and coughing reflex, when the food is swallowed, enters the windpipe are natural or inborn reflexes. Playing a musical instrument and applying brakes are learnt by practice and thus they are conditioned reflexes.

ATP

Reason — During light dependent phase of photosynthesis, the electrons released on splitting of water molecules are used in converting ADP into ATP by adding one phosphate group.

iii, ii, iv, i

Reason — The four major steps in seeing an object arranged in order are:

entry of light rays → focussing of image → transmission of nerve impulses from the retina & brain. → interpretation by the brain

C

Reason — The part C in the picture is a nephron. It is the structural and functional unit of kidney.

A is True, and R is false.

Reason — The seminiferous tubules, located in the testes, are the site where spermatogenesis (the production of sperm cells) occurs. Oxytocin is not involved in sperm production. It is a hormone primarily known for its role in childbirth and lactation in females.

A is False, and R is true

Reason — The nerve impulse travels from the axon of one neuron to the dendrite or cell body of another neuron across a small gap called as synapse.

P and Q

Reason — While playing, the player loses most of water through the sweat glands. Therefore, the kidneys reabsorb most of the water back in the blood to maintain the composition and osmotic pressure of blood. This results in less volume of urine.

Air pollution

Reason — After rainfall the pollutants present in the air are washed away with rain droplets. This clears the air of any pollution.

P and R

Reason — For patients of Diabetes mellitus, it is important to control blood sugar levels by avoiding foods that can cause spikes in blood glucose. Sweets and bananas have high sugar content and therefore, they can spike the blood glucose level.

Cones become active and rods inactive.

Reason — The rods, which are more sensitive to low light and are responsible for vision in dim conditions, become inactive in bright light. In bright light, the cones, which are responsible for colour vision and sharp vision in bright conditions, become active.

plasmolysis and flaccidity

Reason — When a cell of an aquatic plant is placed in a 5% salt solution (which is hypertonic to the cell), water will move out of the cell due to osmosis. This causes the cell membrane to shrink away from the cell wall, leading to plasmolysis. As a result, the cell will lose its firmness, becoming flaccid. Therefore, both plasmolysis and flaccidity will occur.