In the process of respiration – (i) state the function of alveoli. (ii) state the function of stomata. (i) Alveoli in humans: Provide a very large surface area for gas exchange. Thin walls allow oxygen to diffuse into blood and carbon dioxide out. Rich network of capillaries ensures efficient transpRead more
In the process of respiration – (i) state the function of alveoli. (ii) state the function of stomata.
(i) Alveoli in humans: Provide a very large surface area for gas exchange. Thin walls allow oxygen to diffuse into blood and carbon dioxide out. Rich network of capillaries ensures efficient transport of gases.
(ii) Stomata in plants: Tiny pores on leaves regulate exchange of oxygen, carbon dioxide, and water vapor. Guard cells control opening and closing. Help plants balance respiration, photosynthesis, and water loss.
ANSWER: Biological magnification refers to the progressive increase in concentration of harmful, non-biodegradable substances such as pesticides, DDT, or mercury as they pass along a food chain. Producers absorb small amounts from soil or water. Herbivores consume many plants, and carnivores eat sevRead more
ANSWER: Biological magnification refers to the progressive increase in concentration of harmful, non-biodegradable substances such as pesticides, DDT, or mercury as they pass along a food chain. Producers absorb small amounts from soil or water. Herbivores consume many plants, and carnivores eat several herbivores, so the concentration rises at each level.
For example, pesticides sprayed on crops enter grass → eaten by grasshoppers → eaten by frogs → eaten by snakes → eaten by eagles. The eagle, being the top consumer, suffers the maximum effect.
ANSWER: Paralysis of the right side of the body usually indicates damage to the left hemisphere of the cerebrum. The cerebrum controls voluntary actions, learning, memory, and thinking. Each hemisphere controls opposite sides of the body, so damage to the left affects the right side. The motor areaRead more
ANSWER: Paralysis of the right side of the body usually indicates damage to the left hemisphere of the cerebrum. The cerebrum controls voluntary actions, learning, memory, and thinking. Each hemisphere controls opposite sides of the body, so damage to the left affects the right side. The motor area of the cerebrum sends signals to muscles for movement. If injured, nerve impulses cannot pass, causing paralysis.
ANSWER: In pea plants, purple flower (P) is dominant over white (p). When a pure purple (PP) is crossed with a pure white (pp), all F₁ generation plants are Pp, showing purple flowers, as the dominant trait masks the recessive one. When two F₁ plants (Pp × Pp) are self-crossed, the F₂ generation shoRead more
ANSWER: In pea plants, purple flower (P) is dominant over white (p). When a pure purple (PP) is crossed with a pure white (pp), all F₁ generation plants are Pp, showing purple flowers, as the dominant trait masks the recessive one. When two F₁ plants (Pp × Pp) are self-crossed, the F₂ generation shows a genotypic ratio of 1 PP: 2 Pp: 1 pp and a phenotypic ratio of 3 purple: 1 white.
ANSWER: A man can survive with one kidney because a single kidney is capable of performing all essential functions of filtration and excretion. Each kidney contains about one million nephrons, and even one kidney can efficiently remove urea, excess salts, and water from the blood. The remaining kidnRead more
ANSWER: A man can survive with one kidney because a single kidney is capable of performing all essential functions of filtration and excretion. Each kidney contains about one million nephrons, and even one kidney can efficiently remove urea, excess salts, and water from the blood. The remaining kidney compensates by working harder and often enlarges slightly.
However, the person must maintain a healthy lifestyle, avoid overuse of medicines, reduce protein and salt intake, and prevent infections to keep the single kidney functioning properly.
In the process of respiration, – (i) state the function of alveoli. (ii) state the function of stomata.
In the process of respiration – (i) state the function of alveoli. (ii) state the function of stomata. (i) Alveoli in humans: Provide a very large surface area for gas exchange. Thin walls allow oxygen to diffuse into blood and carbon dioxide out. Rich network of capillaries ensures efficient transpRead more
In the process of respiration – (i) state the function of alveoli. (ii) state the function of stomata.
(i) Alveoli in humans: Provide a very large surface area for gas exchange. Thin walls allow oxygen to diffuse into blood and carbon dioxide out. Rich network of capillaries ensures efficient transport of gases.
(ii) Stomata in plants: Tiny pores on leaves regulate exchange of oxygen, carbon dioxide, and water vapor. Guard cells control opening and closing. Help plants balance respiration, photosynthesis, and water loss.
See lessWhat is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
ANSWER: Biological magnification refers to the progressive increase in concentration of harmful, non-biodegradable substances such as pesticides, DDT, or mercury as they pass along a food chain. Producers absorb small amounts from soil or water. Herbivores consume many plants, and carnivores eat sevRead more
ANSWER: Biological magnification refers to the progressive increase in concentration of harmful, non-biodegradable substances such as pesticides, DDT, or mercury as they pass along a food chain. Producers absorb small amounts from soil or water. Herbivores consume many plants, and carnivores eat several herbivores, so the concentration rises at each level.
For example, pesticides sprayed on crops enter grass → eaten by grasshoppers → eaten by frogs → eaten by snakes → eaten by eagles. The eagle, being the top consumer, suffers the maximum effect.
See lessA person has suffered paralysis of the right side of the body. Which part of the brain is likely damaged? Draw a labelled diagram of the human brain and explain.
ANSWER: Paralysis of the right side of the body usually indicates damage to the left hemisphere of the cerebrum. The cerebrum controls voluntary actions, learning, memory, and thinking. Each hemisphere controls opposite sides of the body, so damage to the left affects the right side. The motor areaRead more
ANSWER: Paralysis of the right side of the body usually indicates damage to the left hemisphere of the cerebrum. The cerebrum controls voluntary actions, learning, memory, and thinking. Each hemisphere controls opposite sides of the body, so damage to the left affects the right side. The motor area of the cerebrum sends signals to muscles for movement. If injured, nerve impulses cannot pass, causing paralysis.
See lessIn a pea plant, the trait of flowers bearing purple colour (PP) is a dominant over white colour (pp). Explain the inheritance pattern of F₁ and F₂ generations with the help of a cross following the rules of inheritance of traits. State the visible characters of F₁ and F₂ progenies.
ANSWER: In pea plants, purple flower (P) is dominant over white (p). When a pure purple (PP) is crossed with a pure white (pp), all F₁ generation plants are Pp, showing purple flowers, as the dominant trait masks the recessive one. When two F₁ plants (Pp × Pp) are self-crossed, the F₂ generation shoRead more
ANSWER: In pea plants, purple flower (P) is dominant over white (p). When a pure purple (PP) is crossed with a pure white (pp), all F₁ generation plants are Pp, showing purple flowers, as the dominant trait masks the recessive one. When two F₁ plants (Pp × Pp) are self-crossed, the F₂ generation shows a genotypic ratio of 1 PP: 2 Pp: 1 pp and a phenotypic ratio of 3 purple: 1 white.
See lessHow can a man survive with one kidney?
ANSWER: A man can survive with one kidney because a single kidney is capable of performing all essential functions of filtration and excretion. Each kidney contains about one million nephrons, and even one kidney can efficiently remove urea, excess salts, and water from the blood. The remaining kidnRead more
ANSWER: A man can survive with one kidney because a single kidney is capable of performing all essential functions of filtration and excretion. Each kidney contains about one million nephrons, and even one kidney can efficiently remove urea, excess salts, and water from the blood. The remaining kidney compensates by working harder and often enlarges slightly.
However, the person must maintain a healthy lifestyle, avoid overuse of medicines, reduce protein and salt intake, and prevent infections to keep the single kidney functioning properly.
See less