Class 10 Science - Chapter Life Processes NCERT Solutions | What is the role of saliva in the digest

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?

Five solutions A,B,C,D and E when tested with universal indicator showed pH as 4,1,11,7 and 9, respectively. Which solution is

(a) neutral?
(b) strongly alkaline?
(c) strongly acidic?
(d) weakly acidic?
(e) weakly alkaline?

Arrange the pH in increasing order of hydrogen-ion concentration.

(a) Lithium, sodium, potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements?
(b) Helium is an unreactive gas and neon is a gas of extremely low reactivity. What, if anything, do their atoms have in common?

One-half of a convex lens is covered with a black paper. Will this lens produce a complete image of the object? Verify your answer experimentally. Explain your observations.

Consider a circular loop of wire lying in the plane of the table. Let the current pass through the loop clockwise. Apply the right-hand rule to find out the direction of the magnetic field inside and outside the loop.

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

Besides gallium, which other elements have since been discovered that were left by Mendeléev in his Periodic Table? (any two)

How do Mendel’s experiments show that traits may be dominant or recessive?

Draw the structure for the following compounds.                

       (i)    Ethanoic acid             (ii)   Bromopentane*
       (iii)  Butanone                   (iv)   Hexanal.

*Are structural isomers possible for bromopentane?

What are alloys?

A positively-charged particle (alpha-particle) projected towards west is deflected towards north by a magnetic field. The direction of magnetic field is

   (a) towards south                 (b) towards east
   (c) downward                       (d) upward