Tag: biology

Questions Related to biology

Most abundant constituent of dry air in terms of volume is:

biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

  1. carbon dioxide

  2. helium

  3. nitrogen

  4. oxygen

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Correct Option: C
Explanation:

The most abundant gas in the Earth's atmosphere is nitrogen, which accounts for about 78% of the mass of dry air. 

Oxygen is the next most abundant gas, present at levels of 20 to 21%. 
Although humid air seems like it contains a lot of water, the maximum amount of water vapour that air can hold is only about 4%.

Hence, the correct option is $\text{C}$

In desert areas, water vapor content is :

biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

  1. different

  2. higher

  3. low

  4. constant

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Correct Option: C
Explanation:

In desert areas, water vapour content is low because deserts are hot areas as there is a lack of water and if there is lack of water than there is lack of water vapour.

Evaporation of water in shade is:

biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

  1. fast

  2. faster

  3. slower

  4. none of these

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Correct Option: C
Explanation:

Evaporation of water in shade is slower, as the sun's heat increases the energy of water molecules, and they start moving faster, eventually leading to evaporation when the energy is enough to convert into a gas.

Two forms of oxygen found in the atmosphere are:

biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

  1. water and oxygen

  2. oxygen and carbon dioxide

  3. carbon dioxide and water

  4. oxygen and ozone

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Correct Option: D
Explanation:

The two forms of oxygen found in the atmosphere are

  1. Oxygen, $O _2$
  2. Ozone, $O _3$ is found upper layer of the atmosphere.

Which of the following constituent gas is not directly used by the living beings?

biology natural disasters: winds, storms and cyclones composition of air introduction to air natural resources - air

  1. Oxygen

  2. Nitogen

  3. Hydrogen

  4. Carbon dioxide

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Correct Option: B
Explanation:

Nitrogen gas cannot be used by the human beings directly, breathing pure nitrogen means we're not breathing oxygen, which means that we'll die of oxygen deprivation in a matter of minutes
Hence option B is correct.

If two solution have the same osmolarity, they are said to be

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Hypertonic

  2. Hypotonic

  3. Isotonic

  4. None of the above

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Correct Option: C
Explanation:

Isotonic means two solutions having the same osmolarity. It allows the free movement of water across the membrane without changing the solute concentration. Hypotonic surrounding solution means a solution with less osmolarity. This means that concentration of solutes is less in the surrounding medium, than the concentration of solutes in cell sap and hypertonic surrounding solution means the concentration of solutes is more than the concentration of solutes in the cell sap.

The space between the plasma membrane and the cell wall of a plasmolyzed cell surrounded by a hypertonic solution is occupied by the

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Hypotonic solution.

  2. Isotonic solution.

  3. Hypertonic solution.

  4. Water.

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Correct Option: C
Explanation:

A plant cell wall is fully permeable and it cannot regulate the entry or exit of a solution. When a plant cell is placed in a hypertonic solution it will lose water by exosmosis. This process is called plasmolysis. The protoplasm will shrink and will move inwards and away from the cell wall. As a result, the hypertonic solution will occupy the space between the plasma membrane and the cell wall. Thus the correct answer is option C.

All the following involves osmosis except.

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Water from soil entering a root hair

  2. Water passing from root hair to adjacent cells

  3. Water passing up a xylem vessel element to xylem vessel element above it

  4. Water entering a mesophyll cell from xylem vessel element

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Correct Option: A

At the time of opening of stomata, pH of guard cells in comparison to pH of subsidiary cells, is?

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Higher

  2. Lower

  3. Equal

  4. Uncertain

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Correct Option: A

Two cells A and B are contiguous. Cell A has osmotic pressure $10$atm, turgor pressure $1$ atm and diffusion pressure deficit $3$ atm. Cell B has osmotic pressure $8$ atm, turgor pressure $3$ atm and diffusion pressure deficit $5$ atm. The result will be?

biology movement in and out of the cell transport of molecules osmosis and plasmolysis plant water relation

  1. Movement of water from cell B to A

  2. No movement of water

  3. Equilibrium between the two

  4. Movement of water from cell A to B

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Correct Option: A