Ans. Cells - the bodies of living organisms are made of tiny units called cells.
Cell membrane - The cell is enclosed by a thin outer boundary, called the cell membrane.
Nucleus - Most cells have a distinct, centrally located spherical structure called the nucleus.
Cytoplasm - The nucleus is surrounded by a jelly-like substance called cytoplasm.
Ans. Difference between a parasite and a saprotroph
Parasite |
Saprotroph |
1. They live in or on another organism (its host) and get their nutrients from that host.
|
1. They secrete digestive juices on the dead and decaying matter and convert it into a solution. Then they absorb the nutrients from it. |
2. They feed on living organisms. |
2. They feed on dead and decaying matter. |
3. The organism on which it depends is called host. |
3. They depend upon dead and decaying organisms. |
4. Example of parasite - Cuscuta |
4. Example of saprotroph - Fungi |
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Ans. No, we cannot imagine life on earth in the absence of photosynthesis. In the absence of photosynthesis there would not be any food. The survival of almost all living organisms directly or indirectly depends upon the food made by the plants. Besides, oxygen which is essential for the survival of all living organisms is produced during photosynthesis. In the absence of photosynthesis, life would be impossible on the earth.
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Ans. The pitcher-like structure is the modified part of the leaf. The apex of the leaf forms a lid which can open and close the mouth of the pitcher. Inside the pitcher there are hair which are directed downwards. When an insect lands in the pitcher, the lid closes and the trapped insect gets entangled into the hair. The insect is digested by the digestive juices secreted in the pitcher.
Ans. Plants absorb mineral nutrients from the soil. So, their amounts in the soil keep on declining. Fertilisers and manures contain plant nutrients such as nitrogen, potassium, phosphorous, etc. These nutrients need to be added from time to time to enrich the soil. The bacterium called Rhizobium present in the roots of legumes plants can take atmospheric nitrogen and convert it into a soluble form. This way Rhizobium bacterium also helps to replenish nitrogen in the soil.
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