12. Define the term Egestion. 13. What is meant by Tissue? 14. Explain Symbiosis. 15. What are Monocotyledons? 16. Briefly explain Breathing. 17. Write two characteristics and one example for each of the following: i. Arthropoda ii. Annelida iii. Mollusca 18. State the commercial importance of yeast. 19. Write three points of differences between xylem and phloem. 20. What are allergens? Name any two allergens.
Answers & Comments
Explanation:
12. Egestion refers to the process of eliminating undigested waste materials from the body. It is a part of the digestive system where the indigestible substances, such as fiber and other waste products, are removed from the body through the rectum and anus.
13. Tissue refers to a group of cells that work together to perform a specific function in an organism. It is the building block of organs and plays a vital role in the overall functioning of the body. Examples of tissues include muscle tissue, nerve tissue, and epithelial tissue.
14. Symbiosis is a close and long-term interaction between two different species living together in a mutually beneficial or dependent relationship. It can be classified into three types: mutualism (both species benefit), commensalism (one species benefits while the other is unaffected), and parasitism (one species benefits at the expense of the other).
15. Monocotyledons, also known as monocots, are a group of flowering plants characterized by having a single cotyledon (seed leaf) in their embryos. They are one of the two main groups of angiosperms (flowering plants), with the other being dicotyledons (dicots). Monocots include plants like grasses, lilies, orchids, and palms.
16. Breathing is the process of taking in oxygen from the environment and expelling carbon dioxide from the body. It is essential for the exchange of gases in our respiratory system. When we inhale, oxygen enters our lungs and is transferred to the bloodstream, while carbon dioxide is removed from the bloodstream and exhaled during exhalation.
17.
i. Arthropoda:
- Characteristics: Exoskeleton, segmented body, jointed appendages.
- Example: Insects (such as ants, butterflies), spiders, crustaceans (such as crabs, lobsters).
ii. Annelida:
- Characteristics: Segmented body, bilateral symmetry, presence of setae (bristles).
- Example: Earthworms, leeches.
iii. Mollusca:
- Characteristics: Soft-bodied, usually with a hard shell, muscular foot.
- Example: Snails, clams, octopuses.
18. Yeast has significant commercial importance in various industries, including:
- Baking: Yeast is used as a leavening agent in bread and pastry making, causing dough to rise.
- Brewing: Yeast is essential for fermentation in the production
19. Here are three points of differences between xylem and phloem:
1. Function: Xylem is responsible for transporting water and minerals from the roots to the rest of the plant. Phloem, on the other hand, transports sugars and other organic compounds from the leaves to other parts of the plant.
2. Structure: Xylem is made up of specialized cells called tracheids and vessel elements, which are dead cells joined together to form tubes. Phloem consists of living cells called sieve tube elements and companion cells, which are connected by sieve plates.
3. Direction of Flow: In xylem, the flow of water and minerals is unidirectional, moving upwards from the roots to the leaves. In phloem, the flow of sugars and organic compounds can be bidirectional, moving both upwards and downwards within the plant.
20. Allergens are substances that can trigger an allergic reaction in certain individuals. They are typically harmless substances that cause an abnormal immune response in sensitive individuals. Two common allergens are:
1. Pollen: Pollen from plants, such as grasses, trees, and flowers, can cause allergic reactions in people with pollen allergies (hay fever).
2. Dust mites: Microscopic organisms that live in dust, particularly in bedding, carpets, and upholstery. Dust mite allergens can cause allergic reactions, especially in individuals with dust mite allergies.