Life Processes — Science STD 10 — Question

The germ cell A produced by a person X is round in shape and it fuses with another germ cell B having a long tail and produced by a person Y. The fusion of A and B produces a new cell C. The cell C divides repeatedly and grows inside the organ D of person X to form E in which the body features of the unborn baby are not much developed. E grows further to form F in which the various body features of the unborn baby (like hands, legs, head, eyes, and ears, etc.) can be identified. F grows further and ultimately forms a baby. What are A, B, C, D, E and F? Out of the two persons X and Y, which one is male and which one female?

1. List the parts of the human eye that control the amount of light entering into it. Explain how they perform this function.
2. Write the function of retina in human eye.
3. Do you know that the corneal-impairment can be cured by replacing the defective cornea with the cornea of the donated eye? How and why should we organise groups to motivate the community members to donate their eyes after death?

X and Y are two human beings. The organ A in the reproductive system of X releases a mature gamete B once a month which goes into a tube-like structure C through a funnel-like opening. The organ D in the reproductive system of Y makes and releases gametes E which pass through a duct F and are introduced by an organ of Y, into the body of X. B and E fuse together in C to form a new cell G. The cell G divides repeatedly to form a ball of cells H which gets embedded in the lining of organ I of reproductive system of X where it grows and develops into a baby.

1. Name (i) organ A, and (ii) gamete B.
2. Write two names of tube-like structure C.
3. Name (i) organ D, and (ii) gamete E.
4. Write two names of duct F.
5. Name (i) cell G (ii) ball of cells H, and (iii) organ I.
6. Out of X and Y, which one is (i) male, and (ii) female?

Write one or two words for each of the following statements/ definitions:

• Each level of food chain where transfer of energy takes place.
• The physical factors like temperature, rainfall, light, soil, air and water of an ecosystem.
• Organisms which depend on the producers for food either directly or indirectly.
• The physical and biological world where we live in.
• Selfcontained unit of living things and their non-living environment needing only sunlight for its functioning.

A forest ecosystem having a lot of green plants has some foxes, lions and rabbits in it.

1. Write a food chain comprising all the four organisms mentioned above.
2. Name (i) one herbivore, and (ii) two carnivores, in this food chain.
3. Name the link which is a predator as well as a prey.
4. Name (i) second trophic level, and (ii) third trophic level.
5. Which link of this food chain can feed on second trophic level as well as third trophic level, independently?
6. If the sun provides 1000 J of energy to the plants, then how much energy will be transferred to fox through the food chain.

Arrange the following elements in the increasing order of their metallic character Mg, Ca, K, Ge, Ga.

A filamentous alga X is found in ponds, lakes and slow-moving streams. The filament of this alga simply breaks into two (or more) pieces on maturing and each piece then grows to become a complete new alga.

1. Name an alga which X is likely to be.
2. What is the colour of X?
3. What is the method of forming new algae by the breaking of parent alga known as?
4. An Amoeba also breaks up to form two daughter Amoebae. What is the difference in the splitting of Amoeba and splitting of this alga as a method of reproduction?
5. Name one marine animal which reproduces in the same way as alga X.

There are two similar glands P which are located on top of two similar organs Q in the human body. P are often called the emergency glands and they secrete a hormone R into the blood stream. R is secreted in large amounts when a person is frightened. It brings about temporary changes in the body which allow a lot of substance S from the liver to go into the blood to provide a lot of energy in a very short time. This helps a person to fight back or run away from the frightening situation.
What are P, Q, R and S?

What are the various advantages of water stored in ground?