Class 10 Science - Chapter How do Organism Reproduce? NCERT Solutions | Why is DNA copying an essential part of

Why is variation beneficial to the species but not necessarily for the individual?

Draw a labelled diagram of the longitudinal section of a flower.

What are the functions performed by the testis in human beings?

Why does menstruation occur?

How will an organism be benefited if it reproduces through spores?

Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?

Asexual reproduction takes place through budding in

(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.

How does the embryo get nourishment inside the mother’s body?

What are the advantages of sexual reproduction over asexual reproduction?

How does reproduction help in providing stability to populations of species?

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

What is a good source of energy?

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

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?

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?

A solution reacts with crushed egg-shells to give a gas that turns lime-water milky. The solution contains

  (a) NaCl          (b) HCl          (c) LiCl          (d) KCl

What are the components of the transport system in human beings? What are the functions of these components?

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.

Name

(a) three elements that have a single electron in their outermost shells.
(b) two elements that have two electrons in their outermost shells.
(c) three elements with filled outermost shells.

Ethane, with the molecular formula C₂H₆ has

(a) 6 covalent bonds.
(b) 7 covalent bonds.
(c) 8 covalent bonds.
(d) 9 covalent bonds.

What is the principle of an electric motor?

What kind of mirror – concave, convex or plain – would be best suited for use in a solar cooker? Why?

Use the data in Table 12.2 to answer the following –

(a) Which among iron and mercury is a better conductor?
(b) Which material is the best conductor?

What are the advantages of nuclear energy?

The magnification produced by a plane mirror is +1. What does this mean?