Why is variation beneficial to the species but not necessarily for the individual?
Variations are beneficial to the species than individual because during certain environmental conditions their is so drastic change that their survival of species becomes difficult. For example, if their is sudden rise in temperature of water, then most of the bacteria living in that water would die. So only few variants that can resistant to heat would be able to survive. However, if these few variants were not there, then the entire species of bacteria would have destroyed. Thus, these variants help in the survival of the species.So all variations are not necessarily beneficial for the individual organisms.
When a 12 V battery is connected across an unknown resistor, there is a current of 2.5 mA in the circuit. Find the value of the resistance of the resistor.
Outline a project which aims to find the dominant coat colour in dogs.
Draw the structure for the following compounds.
(i) Ethanoic acid (ii) Bromopentane*
(iii) Butanone (iv) Hexanal.
*Are structural isomers possible for bromopentane?
A hot plate of an electric oven connected to a 220 V line has two resistance coils A and B, each of 24 Ω resistance, which may be used separately, in series, or in parallel. What are the currents in the three cases?
How is the sex of the child determined in human beings?
(a) What property do all elements in the same column of the Periodic Table as boron have in common?
(b) What property do all elements in the same column of the Periodic Table as fluorine have in common?
Calculate the number of electrons constituting one coulomb of charge.
What is an homologous series? Explain with an example.
A man with blood group A marries a woman with blood group O and their daughter has blood group O. Is this information enough to tell you which of the traits – blood group A or O – is dominant? Why or why not?
Give an example of a metal which
(i) is a liquid at room temperature.
(ii) can be easily cut with a knife.
(iii) is the best conductor of heat.
(iv) is a poor conductor of heat.
A solution of a substance 'X' is used for whitewashing.
(i) Name the substance 'X' and write its formula.
(ii) Write the reaction of the substance 'X' named in (i) above with water.
What can you as an individual do to reduce your consumption of the various natural resources?
Where do plants get each of the raw materials required for photosynthesis?
Why do HCl, HNO3, etc., show acidic characters in aqueous solutions while solutions of compounds like alcohol and glucose do not show acidic character?
Describe the structure and functioning of nephrons.
Why should curd and sour substances not be kept in brass and copper vessels?
How is the sex of the child determined in human beings?
What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?
Why is respiration considered an exothermic reaction? Explain.
List two methods of producing magnetic fields.