The "powerhouse" of cell is:

• Nucleus
• Lysosome
• Mitochondria
• DNA
Correct Option: C  [ Mitochondria ]

Remark: Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell's biochemical reactions. Chemical energy produced by the mitochondria is stored in a small molecule called adenosine triphosphate (ATP).

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:

In a forest ecosystem, green plants are

• the primary producers.
• the secondary consumers.
• the decomposers.
• both secondary consumers and decomposers.
Correct Option: A  [ the primary producers. ]

Remark: The green plant in the ecosystem are called producers. In a terrestrial ecosystem, major producers are herbaceous and woody plants. Likewise, producers in an aquatic ecosystem are various species like phytoplankton, algae and higher plants.

To an astronaut in space, the sky appears to be:

• Red
• White
• Dark
• Blue
Correct Option: C  [ Dark ]

Remark:

What does the airbag, used for safety of car driver, contain?

• Sodium bicarbonate
• Sodium azide
• Sodium nitrite
• Sodium peroxide
Correct Option: B  [ Sodium azide ]

Remark:

RADAR is used for

• locating submerged submarines
• receiving signals in a radio receiver
• locating geostationary satellites
• detecting and locating the position of objects such as aeroplane
Correct Option: D  [ detecting and locating the position of objects such as aeroplane ]

Remark:

Which of the following diseases is not caused by bacteria?

• Cholera
• Typhoid
• Tuberculosis
• Chickungunya
Correct Option: D  [ Chickungunya ]

Remark:

Dialysis is prescribed for patients having:

• Liver disease
• Lung trouble
• Kidney trouble
• Heart Disease
Correct Option: C  [ Kidney trouble ]

Remark:

A fan produces a feeling of comfort during hot weather because:

• fan supplies cool air
• our body radiates more heat in air
• conductivity of air increases
• our perspiration evaporates rapidly
Correct Option: D  [ our perspiration evaporates rapidly ]

Remark:

Who invented the contact lens?

• Enrico Fermi
• Adolf Gaston Eugen Fick
• Sandford Fleming
• Benoit Fourneyron
Correct Option: B  [ Adolf Gaston Eugen Fick ]

Remark: