IV. Answer the following questions in long:
1. What do you understand by nutrition? Explain any two modes of nutrition in plants.
2. Why do plants use nitrogen present in the soil? How is this nitrogen replenished in the soil?
3. Explain how green plants prepare their own food.
4. How can you show that sunlight is necessary for photosynthesis?
Answers
1. The process of intaje of food and its proper utilization is called nutrition.
Two modes of nutrition are
Autotrophic - Organism which can synthesis or maje their own food like green plant. They are also called autotrophs.
Heterotrophic - Some living organism depend on other organism for food. All animals incuding humans are eg.
They are also called as heterotrops.
2. When plant do not get enough nitrogen they are unable to produce amino acid. Without amino acid plant cannot make special protein that plants need to grow. Plant and animal waste decompose adding nitrogen to soil.
3. The root take up water and mineral from ground and their leaves absorb a gas called carbon dioxide fron air.
They conver their ingerdient into food by using energy from sun light. This process is called photosynthesis.
And they produce glucose and starch which is their food.
4. Experiment to show that sunlight necessary for photosynthesis.
1. Take a plant with drstarch leave.
2.Leave is partially covered with black paper on which a design is cut.
3. Expose this plant to sunlight for few hours and perform a starch test with iodine solution.