NCERT In Text

Why is diffusion insufficient to meet the oxygen requirements of multi-cellular organisms like humans?

Multicellular organisms such as humans possess complex body designs. They have specialised cells and tissues for performing various necessary functions of the body such as intake of food and oxygen. Unlike unicellular organisms, multicellular cells are not in direct contact with the outside environment. Therefore, diffusion cannot meet their oxygen requirements.

Related Questions Life Processes

Leaves play important role in excretion in plants. Most of the carbon dioxide exits through stomata in leaves. Many excretory products accumulate in leaves. Plants shed leaves to get rid excretory products.

Any visible movement such as walking, breathing, or growing is generally used to decide whether something is alive or not. However, a living organism can also have movements, which are not visible to the naked eye. Therefore, the presence of life processes is a fundamental criterion that can be used to decide whether something is alive or not.

ATP is called the energy currency in living organisms. It is produced in mitochondria during respiration

(a) Cloudy days
Ans. Availability of sunlight is less on cloudy days. This will reduce the rate of photosynthesis.
(b) No rainfall in the area
 Ans. No effect
(c) Good manuring in the area
 Ans. No effect
(d) Stomata get blocked due to dust
 Ans. Opening of stomata is essential for availability of carbon dioxide for photosynthesis. Blockage of stomata will reduce the rate of photosynthesis. 

The plant which is kept in continuous light live longer. We know that plant release carbon dioxide during respiration. In case of plant which is being kept in dark, carbon dioxide will accumulate in the container. This will finally result in lack of oxygen for the plant and plant would die. In case of plant which is being kept in light, carbon dioxide shall be utilized during photosynthesis. This will help in maintaining the availability of oxygen for respiration. As a result, this plant will live longer.