Control and Coordination — Science STD 10 — Question

What are the two properties of carbon which lead to the huge number of carbon compounds we see around us?

A man can read the number of a distant bus clearly but he finds difficulty in reading a book.A man can read the number of a distant bus clearly but he finds difficulty in reading a book.

1. From which defect of the eye is he suffering?
2. What type of spectacle lens should he use to correct the defect?

Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.

In what way are homologous organs evidence for evolution?

A plant has two varieties, one with red petals and the other with white petals. When these two varieties are cross-pollinated, all the offsprings have red petals?

1. Which gene is dominant?
2. Choose suitable letters to represent the two genes.

What is an oxidising agent? Name two oxidising agents which can oxidise ethanol to ethanoic acid.

What is meant by a renewable source of energy? Give two examples of renewable sources of energy.

What is a redox reaction? Explain with an example.

When a person breathes in air, the air enters into his body through an organ Ahaving two holes B in it. The air then passes through pharynx and larynx and enters into a tube C. The tube C divides into two smaller tubes D at its lower end. The two smaller tubes are attached to two respiratory organs E. Each smaller tube divides inside the organs E to form a large number of still smaller tubes called F. The smallest tubes F have air-sacs G at their ends in which gaseous exchange takes place in the body of the person. What are A, B, C, D, E, F and G?

Which of the following belong to the second trophic level?
i. Frog, butterfly, spider, rice weevil
ii. Parrot, frog, butterfly, spider.