BIOLOGY [3 marks Question Answer]

Gymnosperms are plants having naked seeds, i. e., seeds are not enclosed in fruits. The seeds are borne on woody structures called cones, and hence called conifers or coniferous trees. They produce male and female cones for reproduction instead of flowers. Gymnosperms are mostly tall trees growing on mountains. They have well developed roots, thick and woody stems and long needle-shaped leaves. They are evergreen plants.
Examples : Pine, cycas, cedar, Ginkgo, spruce, etc.

(i) On the basis of a place where a plant grows (its habitat), plants are classified into three groups:
(a) Mesophytes : Plants which grow on land and need moderate amount of water, e.g. Potato, tomato.
(b) Hydrophytes : Plants that need maximum water-to grow and hence live in water. They may be floating or partially/completely submerged, e.g. Lotus, Hydrilla.
(c) Xerophytes : Plants that grow on diy land like deserts and need minimum amount of water to live. They have ] tliin and spiny leaves to reduce water loss. e.g. Cactus, babul.
(ii) On the basis of time taken to complete their life cycle, plants are divided into three groups :
(a) Annuals : These plants complete their life cycle in one season in a year. e.g. Wheat, rice.
(b) Biennials : These plants complete their life cycle in two years i.e. in the first year, they bear root, stem and leaves and in the second year, they produce flowers, fruits and seeds, e.g. Carrot, radish, turnip.
(c) Annuals : These plants life for more than two years and bear flowers, fruits and seeds every year. e.g. Mango, Banyan.

Depending on the size, plants are classified into three groups :
(a) Herbs : They are veiy small plants with soft and green Stems. Eg. Mint, spinach.
(b) Shrubs : They are medium sized plants with woody stems. The branches are almost same size arising from the stem immediately above the soil. e.g. Rose, jasmine.
(c) Trees : Tall plants with a thick, hard and woody stem are called trees. They bear woody branches and leaves at some distance above the ground, e.g. Coconut, mango.

Annuals :
a. These plants complete their life cycled one year.
b. These plants germinate, flower and produce seeds within a season.
c. e.g. Maize, wheat, rice.
Perennials :
a. These plants live for many years.
b. They continue to grow and produce flowers for many years.
c. e.g. Mango, banyan, neem.