Question

Aquatic plants are covered with mucilage which
a. Make different part of plant spongy
b. Protects them from pathogen and animals
c. Functions as lubricant
A. a, b
B. b, c
C. a, c
D. All

Answer 1

Hint: Aquatic plants are plants which live and grow in water. A specialized part of aquatic plants is its mucilage. The mucilage plays many important roles in the plant. They are a thick, gluey substance produced even by some microorganisms for defence purposes. Mucilage is edible and It is even used as medicine to soothe irritation by forming a protective film on the skin.

Complete explanation:
Option A a, b: The plant spongy is the squishy middle layer present inside the leaf. It is made up of loosely arranged parenchyma cells. They also have chloroplasts to perform photosynthesis. Mucilage is not related to the sponginess of aquatic plants and hence this option cannot be correct.
Option A is incorrect.
Option B b, c: The mucilage of the aquatic plants does help in keeping pathogens and animals away. The sliminess of the plant due to mucilage traps harmful pathogens and also makes it unfavourable for the animals to consume. It also acts as an excellent lubricant. The lubricant obtained from mucilage is of greater economic importance to humans.
Option B is correct.
Option C a, c: It is known that mucilage does not help in making a spongy part of the plant and hence this option is wrong.
Option C is incorrect.
Option D All: This option cannot be chosen because one of the given statements is wrong in the options.
Option D is incorrect.

Hence, Option B. b, c is the correct answer.

Note:
Mucilage is also produced by land-based plants like plantain, mustard, lady’s finger, flaxseed and carob bean. Here, mucilage protects the plants from wounds and helps in germination and dispersal of seeds. Mucilage is greatly used by humans for various purposes. It is mixed with glue and used as a binding agent. Some are also edible and used as medicine. They have anti-cholesterol, anti-cancer, anti-diabetic and laxative properties.