What is the importance of DNA copying in reproduction?
Reproduction is a process by which every living organism makes a copy like itself as seen in parents to their children. This is only done because of replication of DNA (deoxyribonucleic acid) by transferring the genetic information from the parents to their offsprings or simply we can say that passing their physical or mental character genetically to main the chromosome number of species.
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?
Calculate the number of electrons constituting one coulomb of charge.
Only variations that confer an advantage to an individual organism will survive in a population. Do you agree with this statement? Why or why not?
What are the necessary conditions for autotrophic nutrition and what are its by-products?
How is oxygen and carbon dioxide transported in human beings?
Name two energy sources that you would consider to be renewable. Give reasons for your choices.
How is the amount of urine produced regulated?
You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in Table 10.3.
Material medium |
Refractive index |
Material medium |
Refractive index |
Air | 1.0003 | Canada Balsam |
1.53 |
Ice | 1.31 | ||
Water | 1.33 | Rock salt | 1.54 |
Alcohol | 1.36 | ||
Kerosene | 1.44 | Carbon disulphide |
1.63 |
Fused quartz |
1.46 | ||
Turpentine oil |
1.47 | Ruby | 1.71 |
Benzene | 1.50 | Sapphire | 1.77 |
Crown glass |
1.52 | Diamond | 2.42 |
Why should curd and sour substances not be kept in brass and copper vessels?
A solar water heater cannot be used to get hot water on
(a) a sunny day. (b) a cloudy day.
(c) a hot day. (d) a windy day.
How do we detect the smell of an agarbatti (incense stick)?