The red, orange and yellow colours of leaves are due to

• lignins

• carotenoids

• aldehydes

• tannins

The disease that kills more people than lung cancer as a consequence of air pollution is

• heart attack

• chronic bronchitis

• asthma

• emphesema

183.

Bark of this tree is used as a condiment

• Cinnamon

• Clove

• Neem

• Palm

Saliva helps in the digestion of

• Fats

• Starch

• Proteins

• Vitamins

The longest bone in the human body is

• Ulna

• Humerus

• Femur

• Tibia

Which of the following is the smallest bird?

• Pigeon

• Parrot

• Humming bird

• House sparrow

The optimum dissolved oxygen level (in mg/litre) required for survival of aquatic organisms is

• 4-6

• 2-4

• 8-10

• 12-16

Iodoform is used as an

• antipyretic

• analgesic

• antiseptic

• anaesthetic

An artificial ecosystem is represented by

• pisciculture tank

• agricultural land

• zoo

• aquarium

Red data book gives information about species which are

• extinct

• endangered

• dangerous

• rare