81. How do most insects respire?

  1. Through skin
  2. Through gills
  3. By Lungs
  4. By tracheal system

View Answer/Explanation

Answer – (4)

It lies on a network of small tubes that channel O2 directly to the different parts of the body.

82. Which of the following is not a digestive enzyme in the human system?

  1. Trypsin
  2. Gastrin
  3. Ptyalin
  4. Pepsin

View Answer/Explanation

Answer – (2)

Gastrin is a hormone that stimulates the secretion of the digestive enzyme in the stomach.

83. The release of which one of the following into ponds and wells helps in controlling the mosquitoes?

  1. Crab
  2. Dogfish
  3. Gambusia fish
  4. Snail

View Answer/Explanation

Answer – (3)

Gambusia affinis is larvivorous, which controls the mosquitoes by eating mosquito larvae, insects and crustaceans.

84. Which among the following is not a good source of nutritional calcium?

  1. Rice
  2. Ragi
  3. Skimmed Milk
  4. Egg

View Answer/Explanation

Answer – (2)

85. Which one of the following is a membrane that protects the developing embryo from desiccation?

  1. Amnion
  2. Chorion
  3. Allantois
  4. Yolk sac

View Answer/Explanation

Answer – (1)

Amnion is formed above the embryo. It protects by a fluid-filled space called the amniotic cavity.

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