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Differences: 1 Mark each
Any two:

Answer: Option A. ->
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Each point: 1 Mark
The diaphragm is the muscular sheet that separates the abdomen from the chest cavity..
The diaphragm is a thin sheet of muscle that sits at the base of the chest and separates the abdomen from the chest. It contracts and flattens when you inhale. This creates a vacuum effect that pulls air into the lungs. When you exhale, the diaphragm relaxes and the air is pushed out of lungs.

Answer: Option A. ->
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Respiration: 1 Mark each
 
1. In plants different parts can take independently take in oxygen and give out carbon dioxide. Leaves take in oxygen from the air and give out carbon dioxide through tiny pores called stomata.
2. In the cells, this oxygen is used to break down glucose into carbon dioxide and water with the release of energy. 
3. Like all living cells roots also need oxygen to generate energy. Roots take up air from the air spaces present between the soil particles. 

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Each point: 1 Mark
Some features of the alveoli that allow this are as follows:

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  they increase the surface area in lungs for absorption 

  
  


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  they have thin walls (just one cell thick)

  
  


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  they have a lot of tiny blood vessels called capillaries.

  
  

 

Answer: Option A. ->
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Functions: 1 Mark each
1. Diaphragm and ribs help in breathing activity.
2. During inhalation, ribs move up and diaphragm moves down to increase the chest cavity space. Lungs get filled with air.
3. During exhalation, ribs move down and diaphragm moves up to its former position. This reduces chest cavity space and air is pushed out.

Answer: Option A. ->
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Each Point: 1 Mark
1. Fishes breathe through special structures called gills. Gills are present on either side of their heads and are rich with blood vessels. 
2. Fishes take in oxygen dissolved in water. During respiration, water enters the body through mouth, passes through gills and comes out of the operculum. 
3. Gases are exchanged in the gills. They absorb the oxygen and expel carbon dioxide.

Answer: Option A. ->
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Spiracles: 1 Mark
Organism: 1 Mark
Function: 1 Mark 
Spiracles are small openings present on the sides of the body of insects, like cockroaches.
Spiracles help in entry and exit of gasses for respiration.

Answer: Option A. ->
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Types: 1 Mark each
Cells need a source of energy. They get this energy by breaking down glucose obtained from the food. This process is called 'cellular respiration'. 
There are 2 types of cellular respiration - 
During aerobic respiration, glucose is broken down into carbon dioxide and water in the presence of oxygen to release energy. 
During anaerobic respiration, glucose is broken down into alcohol and carbon dioxide in the absence of oxygen to release a little bit of energy.

Answer: Option A. ->
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Statement and justification: 1 Mark each
(1) False. During heavy exercise, more oxygen is required to meet extra demand of energy. Therefore breathing rate increases.
(2) False. Photosynthesis occurs in the presence of sunlight. Respiration is a continuous process and occurs all the time (day and night).
(3) True. Frogs breathe through skin as well as through lungs. Thus they have moist-slippery skin and lungs to help them breathe on both land and water.
(4) True. At high altitudes, the lower air pressure makes it more difficult for oxygen to enter our respiratory systems. That is why mountaineers carry oxygen with them.
(5) True. Muscle cells break down glucose into lactic acid with the release of energy in the absence oxygen during heavy activities. This process is called anaerobic respiration.

Answer: Option A. ->
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First 3 points: 1 Mark each
Equations: 1 Mark each