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.

If plant is releasing carbon dioxide and taking in oxygen during the day, it means that respiration is happening in plant. But it does not mean that photosynthesis is not happening. Carbon dioxide released after respiration comes out of stomata. For photosynthesis, the plant takes in carbon dioxide from atmosphere. In other words, plant does not depend on respiration for carbon dioxide for photosynthesis.

Fish can take in oxygen which is dissolved in water. For this, they show adaptation in the form of gills. But fish does not have the ability to utilize oxygen from air. Due to this, a fish can comfortably live in water but dies when it is taken out of water.

Autotroph	Heterotroph
1. Organisms that prepare their own food.	1. Organisms that are dependent on other organisms for food.
2. They have chlorophyll.	2. They lack chlorophyll.

Nutrition is required by every organism for various purposes. An organism needs energy to carry out various activities, and this energy comes from food. An organism also needs raw materials for growth and repair. These raw materials come from food. This shows that nutrition is a necessity for an organism.

Green plants are the main conducts through which solar energy is trapped and channeled to all other organisms. Green plants are the main source of food (directly or indirectly) for most of the heterotrophs. Without green plants, no animal shall be able to get food and thus no animal would survive. Hence, almost all life forms would be wiped out if green plants disappear from earth.

If leaves of a healthy potted plant are coated with Vaseline, it will clog the stomatal pores on leaves. Blockage of stomata will stop transpiration and exchange of gases from leaves. Transpiration plays an important role in ascent of sap in plants. Hence, lack of transpiration will stop ascent of sap. Moreover, stoppage of exchange of gases would also stop respiration and photosynthesis in leaves. This will result in death of leaves and finally the plant would die due to lack of food.

Aerobic respiration	Anaerobic respiration
1. Oxygen is utilised for the breakdown of respiratory substrate.	1. Oxygen is not required.
2. It takes place in cytoplasm (glycolysis) and inside mitochondria (Krebs cycle)	2. It takes place in cytoplasm only.
3. End products are carbon dioxide and water	3. End products are lactic acid or ethanol and carbon dioxide.
4. More energy is released.	4. Less energy is released.