P-2 Life Processes in Living Organisms Part – 1 — Science STD 10 — Question

There were lot of organisms A in the crop fields in an area. These organisms used to feed on organisms B also present in the crop fields but which damaged the standing crops. One day some people arrived in the fields and killed all the organisms A so that they could remove their C for making fancy items which were in great demand. Due to large scale killing of A, the population of B increased too much damaging all the crops in the area and causing a famine-like situation. Apart from A, there is another organism D which can also kill and eat B. Name A, B, C and D.

Explain in brief the sensitive issues of general public about disaster.
(OR)
Which are the three aspects of disaster tjiat are important for common citizens?

When a person eats sugary food, then organisms A present in his mouth act on sugar to produce a substance B. The substance B first dissolves the calcium salts from the top part C of the tooth and then from its middle part D forming holes E. These holes ultimately reach the part F in the lower part of tooth which contains nerves and blood vessels. The substance B irritates the nerve endings inside the tooth causing toothache.

1. What are (i) organisms A, and (ii) substance B?
2. What are (i) part C, and (ii) part D, of tooth known as?
3. By what name are the holes E in the tooth known?
4. Name the part F of the tooth.
5. What will happen if organisms A reach part F of the tooth known?

Answer the questions based on Modern Periodic table.
Use your brain power;

Element	O	B	C	N	Be	Li
Atomic radius(pm)	66	88	77	74	111	152

Question
(i) By referring to the Modern Periodic table find out the period to which the above elements belong?
(ii) Arrange the above elements in a decreasing order of their atomic radii.
(iii) Does this arrangement match with the pattern of the second period of the Modern Periodic table.
(iv) Which of the above elements have the biggest and the smallest atom?
(v) What is the periodic trend observed in the variation of atomic radius while going from left to right within a period?

Comparative study of all the four-blocks of Modern Periodic table.

Differentiate between myopia and hypermetropia. What type of spectacles should be worn by a person having the defects of myopia as well as hypermetropia? How does it help?

How do the interactions take place in the biotic and abiotic factors of ecosystem?

Refraction observed in the atmosphere.

A person buys two electrical devices P and Q for lighting purposes in his house. The device P consumes only 5 units of electricity in a month but device Q consumes 15 units of electricity in a month when used for the same number of hours daily. The device Q wastes a lot of electricity by radiating energy C but P does not do so.

1. What type of device is (i) P, and (ii) Q?
2. Name one component which is present in Q but not in P.
3. Name the energy C.
4. Which device is more energy efficient: P or Q?
5. Which fossil fuel is most likely to be conserved if all of us switch over to devices like P?

What is meant by refining of a metal? Name the most widely used method for the refining of impure metals obtained by various reduction processes. Describe this method with the help of a labelled diagram by taking the example of any metal.