P-1 Effects of electric current — Science STD 10 — Question

X, Y, and Z are three animals. The animal X can fly but animal Y can only run on ground or walls. The forelimbs of animals X and Y have the same basic design but they are used for different purposes such as flying and running respectively. The animal Z became extinct an long time ago. The study of fossils of Z tells us that it had some features like those of X and some like those of Y. In fact, Z is said to form a connecting link in the evolutionary chain of X and Y.

1. What could the animals X, Y and Z be?
2. What name is given to the forelimbs like those of X and Y which have the same basic design but different functions?
3. Name one feature in which Z resembled X.
4. Name one feature in which Z resembled Y.
5. Which is the correct evolutionary chain involving X, Y and Z : X → Z → Y or Y → Z → X?

Which principle is used to measure the specific heat capacity of a substance?

When a female child is born, her ovaries already contain thousands of immature eggs (or ova) contained in immature structures A. On maturing, A bursts open and an egg shoots out of the ovary in a process called B. The process B starts in the females at puberty and occurs again and again after a time period x. Before every occurrence of process B, the inner lining of uterus becomes thick and soft with lots of blood vessels in it. When the egg cell gets fertilised by a sperm, then an event C occurs in the life of mature human female which lasts for time period y leading to the birth of baby. If, however, the egg cell released by the ovary does not get a sperm to fuse with, then the thick and soft inner lining of uterus breaks down and comes out of the female's body in an event called D. The occurrence of event D is controlled by chemical substances E.

1. What are A?
2. What is process B?
3. What is the time period x?
4. Name the event C.
5. How much is the time period y?
6. What is the name of process D?
7. Name the chemical substances E.

What are the objectives of mock drill?

Describe the merits of Mendeleev’s periodic table?

How can we offer first aid to victims of any disaster?

What do we learn from the story of Jadav Molai Peyang?

Define ‘speciation’. Explain how speciation occurs.

Write answer as directed.
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