STD 4, CHAPTER 4: PLANTS AROUND US, EXTRA QUESTION AND ANSWERS

1.      Define habitat.

Ans: The place, where a living thing lives most comfortably, is called its habitat. The habitat is thus, the natural home of a living thing.

2.      Define terrestrial plants.

Ans: Plants which grow on land, are called terrestrial plants.

3.      List the different habitats of terrestrial plants.

Ans: The different habitats of terrestrial plants are, Hills, plains, hot and wet regions, marshy areas, desert areas, etc.

4.      Name some plants which grow on the hills.

Ans: Pine, deodar, cedar, spruce and fir, grow on the hills.

5.      What is the shape of the plants of the hills?

Ans: Plants of the hills, generally have a conical shape.

6.      What is the shape of the leaves of the plants of hills?

Ans: The leaves of the plants of hills are narrow and needle shaped.

7.      How does the conical shape help the plants of hills?

Ans: The conical shape of these trees does not allow snow to get deposited on them.

8.      Name some plants that grow in plains.

Ans: Peepal, banyan, mango, sal, sheesham, grow in plains.

9.      Name the plants growing in hot and wet regions.

Ans: Teak, rubber, coconut, pepper, cotton, rice and banana grow in hot and wet regions.

10.  Why are the trees, of hot and wet regions called ‘evergreen trees’?

Ans: i) The trees of hot and wet regions generally have a large number of leaves.

ii) They shed their leaves gradually.

So, they are called evergreen trees.

11.   Define a marshy area.

Ans: Marshy area means a very wet, muddy area on land.

12.  Name the plants growing in marshy areas.

Ans: Mangroves grow in marshy areas.

13.  Why do roots of mangroves come out of the soil?

Ans: Roots of mangroves come out of the soil, to get oxygen.

14.  What are ‘breathing roots’ or ‘aerial roots’?

Ans: The roots that come out of the soil, above the water level, and take oxygen from air, are called breathing roots or aerial roots.

15.  Name the plants having aerial roots.

Ans: Banyan, maize and mangroves, have aerial roots.

16.   How is cactus plant able to grow in desert conditions?

Ans: i) It can survive in soil that has very little water.

ii) It has a green stem and well developed roots. The stem stores water.

iii) Cactus plant has spines instead of leaves.

17.  What is the meaning of the term, ‘Aquatic’?

Ans: Aqua means ‘water’ and aquatic means ‘existing or happening in water’.

18.  Define aquatic plants.

Ans: Plants, found in water, are called aquatic plants.

19.   What are the two types of aquatic plants?

Ans: The two types of aquatic plants are, i) Floating Aquatic plants

                                                                          ii) Underwater plants

20.  What are the two types of Floating aquatic plants?

Ans: The two types of Floating aquatic plants are, i) Free Floating Plants

                                                                                         ii) Fixed Aquatic plants

21.  Name some Free floating aquatic plants.

Ans: Water lettuce, water hyacinth and duckweed are the free floating aquatic plants.

22.  Why some plants float on the surface of water?

Ans:i) Some plants are not attached to any surface.

ii) They have air filled cavities in their leaves and stems.

iii) These cavities make them light and help them to easily float on water.

23.  Name some fixed aquatic plants.

Ans: Lotus and water lily are the fixed aquatic plants.

24.  What type of leaves do the fixed aquatic plants have?

Ans: The fixed aquatic plants have broad leaves.

25.  Name the stem which is eaten as a vegetable.

Ans: The stem of lotus (kamal kakri), is eaten as a vegetable.

26.  Name an underground plant. What kind of leaves does it have?

Ans: Hydrilla is an underground plant. It has pointed and strap-like leaves.

27.  How does the Hydrilla plant help the aquatic animals?

Ans:i) Hydrilla increase the oxygen content of water and remove carbon dioxide from it.

ii) This helps in making water suitable for fish and other aquatic animals and helps them to get enough oxygen.

28.  What are cultivated plants?

Ans: Those plants which are grown in the fields by the farmers, are called as cultivated plants.

29.  What is ploughing?

Ans: The process of digging the soil or loosening the soil, is called ploughing.

30.  How ploughing is done?

Ans: Ploughing is done with the help of a plough or a tractor.

31.  An iron structure used in the process of ploughing, is called a _________.

Ans: Plough

32.  What are weeds?

Ans: The undesirable plants in the field are called as weeds.

33.  Why should weeds be removed from the fields?

Ans: Weeds are removed so that they do not consume water and fertilisers meant for the main crop.