How do Organisms Reproduce? — Science STD 10 — Question

Why do fishes die when taken out of water?

i. Why does carbon form the largest number of compounds? Give two reasons.
ii. Why are some of these called saturated and the other unsaturated compounds?
iii. Which one of these two is more reactive and why?

Name two animals having cutaneous respiration. What special features of the skin make cutaneous respiration effective?

A person needs a lens of power –5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision, and (ii) near vision?

Explain why the tongue may be considered as both a receptor and an effector organ.

An element X combines with oxygen to form an oxide XO. This oxide is electrically conducting.

1. How many electrons would be there in the outermost shell of the element X?
2. To which group of the periodic table does the element X belong?
3. Write the formula of the compound formed when X reacts with chlorine.

Write down a formula for the magnification produced by a concave mirror.

1. In terms of height of object and height of image.
2. In terms of object distance and image distance.

Express the following facts in the form of a balanced chemical equation:“When a strip of copper metal is placed in a solution of silver nitrate, metallic silver is precipitated and a solution containing copper nitrate is formed”.

What is the function of insulin hormone? What type of patients are given insulin injections?

A person having short-sight cannot see objects clearly beyond a distance of 1.5 m. What would be the nature and power of the corrective lens to restore proper vision?