What could be the reasons for adopting contraceptive methods?
There can be many reasons for adopting contraceptive methods:-
The main reason for adopting the contraceptive methods is birth control or the population control.
Condoms are the safeguard against the infection of AIDS (acquired immune deficiency syndrome) or STD (sexually transmitted diseases)
The induced abortion method of contraception is used to get rid of unwanted pregnancy by the unprotected intercourse, when women get raped by someone, or where mother’s life or foetus is in danger and when women is not able to conceive the baby due to the weak immune system of the baby.
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?
We saw in this chapter that there are four main stakeholders when it comes to forests and wildlife. Which among these should have the authority to decide the management of forest produce? Why do you think so?
What is the role of the split ring in an electric motor?
How can you as an individual contribute or make a difference to the management of (a) forests and wildlife, (b) water resources and (c) coal and petroleum?
The human eye can focus on objects at different distances by adjusting the focal length of the eye lens. This is due to
(a) presbyopia.
(b) accommodation.
(c) near-sightedness.
(d) far-sightedness.
Suggest some approaches towards the conservation of forests.
Compare the above system with the probable systems in hilly/mountainous areas or plains or plateau regions.
Two circular coils A and B are placed closed to each other. If the current in the coil A is changed, will some current be induced in the coil B? Give reason.
Define 1 dioptre of power of a lens.
Do basic solutions also have H+(aq) ions? If yes, then why are these basic?
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