BIOLOGY [2 Mark Question Answer]

Since bryophytes grow on land but need water for reproduction (like frogs in animals), they are called the amphibians of the plant kingdom.

The presence or absence of flowers and seeds in a plant forms the basis of the classification of plants into flowering plants (Cryptogams) and non-flowering plants (Phanerogams).

Two important features of angiosperms are:

1. They are plants with well-developed roots, stems, leaves, and flowers.
2. They produce seeds which are enclosed in a fruit.

Characteristics of pteridophytes (ferns) are :

1. These are non-flowering plants that do not produce seeds.
2. These plants grow in damp and shady areas.
3. The leaves are feather-like and called fronds. (Pteron means feather and phyton means plants). They are divided into leaflets.
4. They reproduce through spores box on the lower side of fronds in small rounded brown structures called sori.
5. The plants either have underground stems called rhizome or stem above the ground.

Bryophytes are those non-flowering plants that grow on moist land and need water to reproduce. They are also called the amphibians of the Plant Kingdom, e.g. Mosses, liverworts.

1. Seed bearing plants are called phanerogams.
2. Non-seed bearing plants are called cryptogams.

Cryptogams are non-flowering plants that do not produce seeds and flowers. They are further categorized into Thallphyta (Algae, Bacteria, Fungi), Bryophyta (Mosses), and Pteridophyta (Ferns).

Excess of water from the body of the amoeba is collected in the contractile vacuole. Ammonia is soluble in water. Hence, sometimes ammonia is expelled out along with the water from the contractile vacuole.
Function:The contractile vacuole expands when there is water in it and shrinks when the water is released into the surrounding.

The body of Amoeba is irregular in shape. The outer covering of the body is the cell membrane. A prominent nucleus lies in the center surrounded by cytoplasm.

There are four common forms of bacteria – coccus, bacillus, spirillum, and vibrio.

1. Coccus form:These bacteria are spherical or ovoid in shape.
2. Bacillus form (bacillus: rod) These are rod-shaped. These may also occur singly or in a group of two’s or three’s, joined end to end in long chains.
3. Spirillum form:These are spiral-shaped.
4. Vibrio form: These are short, curved, appearing comma-shaped. Chloera bacteria (Vibrio cholerae) are of vibrio type.