Biological Classification — BIOLOGY STD 11 Science — Question

What are three major types of cells found in the gastric glands? Name their secretions.

Which features make mammals as the most successful and dominant animals?

Name the scientists who proposed the cell theory. Also, list its main postulates.

Draw the labelled diagram of the following: Gram seed.

How are gibberellins useful in agriculture to improve productivity? Give three points in support of your answer.

What essential role does the root endodermis play during mineral absorption in plants?

How are muscles classified based on their location? Mention their important functions.

Give reason for each of the following:

1. The vascular bundles of an isobilateral leaf are near similar in size, except that in the midrib.
2. Heart wood is dark brown in colour.
3. Cells of phellem/cork are impervious to water.
4. Quantity of secondary xylem produced is more than the quantity of secondary phloem during secondary growth.
5. Phellogen is a secondary meristem.

Differentiate between the following: Diffusion and Osmosis

Every nutrient comes from the abiotic component of the ecosystem. These nutrients are converted by green plants into useful substances and finally go to other living beings through the food chain. Finally, after the death of plants and animals; decomposers send them back to the environment. Thus the balance of various components of the ecosystem is maintained. In your view which of the following is the correct approach? What is the importance of balance of ecosystem for us?

1. We should protect the ecosystem so that its balance is maintained.
2. We should enjoy our life and let the nature do its job of maintaining the balance in the ecosystem.