A: Glycogen

B: Protein

C: Starch

D: Fatty acid

Solution:

Solution:

Explanation

Reasons for adopting contraceptive methods:

Prevent unwanted pregnancies

Family planning and population control

Prevent STD’s (sexually transmitted diseases)

Final Answer

Hence are few of the reasons to adopt contraceptive methods.

Solution:

Explanation :-

Arteries and veins both are blood vessels. 

Arteries carry oxygenated blood away from the heart.

Arteries do not have valves.

Artery walls are thicker than veins because blood flows at very high pressure in arteries.

Veins carry deoxygenated blood from all over the body parts to the heart,

Veins have valves.

Vein walls are thinner than arteries because blood flows at a lower pressure than in arteries.

Both arteries and veins are joined by a network of thin blood vessels known as capillaries.

Capillaries are the thinnest blood vessels.

Final answer :-

capillaries.

A: Rice - field

B: Forest

C: Grassland

D: Lake

Solution:

Explanation

Forest, grassland and lake are naturally occurring ecosystems.

While, rice-field is formed by humans for the purpose of agriculture.

As it is not formed naturally it is an artificial ecosystem.

Final Answer

Hence, option A. i.e., Rice - field is the correct answer.

A: Leg of man, leg of horse, wing of bat.

B: Hand of man, tail of horse, wing of bat.

C: Hand of man, forelimb of horse, wing of bat.

D: Hand of man, leg of horse, wing of bat.

Solution:

Explanation:

The word homo in homologous means the ‘same’.

The organs that have the same origin i.e. same structure but perform different functions. Such organs are known as homologous. 

Final Answer: 

Hence the correct answer is C i.e. Hand of man, forelimb of horse, wing of bat.