Which of the following contains maximum carbon dioxide ?

• Grasslands
• Forests
• Oceans
• Agroecosystems
Correct Option: C  [ Oceans ]

Remark:

The number of milk teeth in man is

• 28
• 29
• 20
• 12
Correct Option: C  [ 20 ]

Remark:

Which of the following cell organelles is referred to as the 'suicidal bags' or 'disposal units' ?

• Lysosome
• Peroxisomes
• Glyoxisomes
• Mtochondria
Correct Option: A  [ Lysosome ]

Remark:

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

• 4-6
• 2-4
• 8-10
• 12-16
Correct Option: A  [ 4-6 ]

Remark:

What happens to a person who receives the wrong type of blood?

• all the arteries constrict
• all the arteries dialate
• the RBCs agglutinate
• the spleen and lymph nodes deteriorate
Correct Option: C  [ the RBCs agglutinate ]

Remark:

The acid present in the stomach of human beings is:

• HNO₃
• H₂CO₃
• HCl
• H₂SO₄
Correct Option: C  [ HCl ]

Remark:

What chemicals are used in fire extinguishers used in houses and offices ?

• Water, potassium bicarbonate and fluorocarbon
• Water, calcium hydroxide and chlorofluorocarbons
• Water, potassium hydroxide and chlorobenzene
• None of these
Correct Option: A  [ Water, potassium bicarbonate and fluorocarbon ]

Remark:

A heavy stone appears to be lighter in water. This is due to

• Upward pressure of water
• Downward pressure of water
• Lateral pressure of water
• None of these
Correct Option: A  [ Upward pressure of water ]

Remark: Water creates upward pressure due to the principle of buoyancy, as described by Archimedes' principle.

Which of the following statements is correct ?

• Protons are negatively charged and are present in the nucleus
• Electrons are positively charged and are present in the nucleus
• Electrons are negatively charged and are present in the orbits
• The entire mass of atom is distributed in the orbits
Correct Option: C  [ Electrons are negatively charged and are present in the orbits ]

Remark:

Einstein received Nobel Prize for his theory of :

• Relativity
• Photoelectricity
• Brownian Motion
• None of these
Correct Option: B  [ Photoelectricity ]

Remark: