Class 10 Science - Chapter Life Processes NCERT Solutions | How are the alveoli designed to maximise

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

How is the amount of urine produced regulated?

What are the different ways in which glucose is oxidised to provide energy in various organisms?

What criteria do we use to decide whether something is alive?

The breakdown of pyruvate to give carbon dioxide, water and energy takes place in

        (a) cytoplasm.               (c) chloroplast.
        (b) mitochondria.           (d) nucleus.

What are the differences between autotrophic nutrition and heterotrophic nutrition?

What are outside raw materials used for by an organism?

What are the components of the transport system in highly organised plants?

What would be the consequences of a deficiency of haemoglobin in our bodies?

What advantage over an aquatic organism does a terrestrial organism have with regard to obtaining oxygen for respiration?

Did Döbereiner’s triads also exist in the columns of Newlands’ Octaves? Compare and find out.

What is a good source of energy?

What are trophic levels? Give an example of a food chain and state the different trophic levels in it.

What changes can you make in your habits to become more environment-friendly?

What is the difference between a reflex action and walking?

What is the importance of DNA copying in reproduction?

If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same population, which trait is likely to have arisen earlier?

Why should a magnesium ribbon be cleared before burning in air?

Define the principal focus of a concave mirror.

You have been provided with three test tubes. One of them contains distilled water and the other two contain an acidic solution and a basic solution, respectively. If you are given only red litmus paper, how will you identify the contents of each test tube?

Which uses more energy, a 250 W TV set in 1 hr, or a 1200 W toaster in 10 minutes?

An electric heater of resistance 8 Ω draws 15 A from the service mains 2 hours. Calculate the rate at which heat is developed in the heater.

A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R′, then the ratio R/R′ is –

(a) 1/25        (b) 1/5        (c) 5        (d) 25

Why is damage to the ozone layer a cause for concern? What steps are being taken to limit this damage?

An electric bulb is rated 220 V and 100 W. When it is operated on 110 V, the power consumed will be –

(a) 100 W          (b) 75 W          (c) 50 W          (d) 25 W

Which of the following lenses would you prefer to use while reading small letters found in a dictionary?

(a) A convex lens of focal length 50 cm.
(b) A concave lens of focal length 50 cm.
(c) A convex lens of focal length 5 cm.
(d) A concave lens of focal length 5 cm.

What were the limitations of Döbereiner’s classification?

What effect does the concentration of H⁺(aq) ions have on the nature of the solution?

Which one of the following materials cannot be used to make a lens?

(a) Water        (b) Glass        (c) Plastic        (d) Clay

How could the Modern Periodic Table remove various anomalies of Mendeléev’s Periodic Table?