Draw a labelled diagram of the longitudinal section of a flower.
Why is variation beneficial to the species but not necessarily for the individual?
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?
Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.
Can you think of reasons why more complex organisms cannot give rise to new individuals through regeneration?
How does the embryo get nourishment inside the mother’s body?
What is the importance of DNA copying in reproduction?
How does reproduction help in providing stability to populations of species?
What are the advantages of sexual reproduction over asexual reproduction?
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?
The breakdown of pyruvate to give carbon dioxide, water and energy takes place in
(a) cytoplasm. (c) chloroplast.
(b) mitochondria. (d) nucleus.
How is the concentration of hydronium ions (H3O+) affected when a solution of an acid is diluted?
Name the sodium compound which is used for softening hard water.
An object 5 cm in length is held 25 cm away from a converging lens of focal length 10 cm. Draw the ray diagram and find the position, size and the nature of the image formed.
Why is sodium kept immersed in kerosene oil?
Why do you think that there should be equitable distribution of resources? What forces would be working against an equitable distribution of our resources?
What are alloys?
What is biological magnification? Will the levels of this magnification be different at different levels of the ecosystem?
How is the amount of urine produced regulated?
How does the electronic configuration of an atom relate to its position in the Modern Periodic Table?