NCTB Class 8 science Chapter 4 “Reproduction and Secretion” Solution
Bangladesh Board Class 8 science Solution Chapter 4 “Reproduction and Secretion” Exercises Question and Answer by Experienced Teacher.
NCTB Solution Class 8 Chapter 4 “Reproduction and Secretion”
NCTB Bangladesh Board
“Reproduction and Secretion”
Fill in the blanks:
(1) Reproduction is mainly of two types, —- and ——.
Answer:- Sexual, asexual.
(2) When fruit develops from single ovary, the fruit is called ———.
Answer:- Simple fruit.
(3) The flower which bears —-part, is known as complete flower.
(4) Pollination is of two types —- and —–.
Answer:- Self, Cross.
(5) When all the flowers of an inflorescence together from a fruit, it is known as —- fruit.
(6) Ovule of the matured fruit develops into—–.
Short Answer Questions:
(1) Why asexual reproduction is important for plants?
Answer:- Asexual reproduction is important for plants because by this reproduction offspring arise from a single parent and inherit the genes of that parent only. The off spring will be exact genetic copies of the parent.
(2) Why grafting is made from mango tree?
Answer:- Grafting is made from mango tree because if we covered a cut of mango tree soil, cow dung and keep it moist by regular watering then the root will grow in a couple of days.
Multiple Choice Questions:
(1) Which one of the following is aggregate fruit?
Answer:- Custard apple.
(2) Which one is the characteristic of insect-pollinated flowers?
Answer:- They are colourful and bears nectar gland.
(3) Which part receives pollen grains?
(4) P part of the figure-
Answer:- (i) & (iii).
(1) (a) What is reproduction?
Answer:- A complex process by which an organism produces its off springs is known as reproduction.
(1) (b) what do you mean by pollination?
Answer:- Pollination is the transfer of pollen grains from anthers to stigmas.
(1) (c) Draw a labelled diagram of the longitudinal section of the plant constituted by M,N.O and P parts.
Answer:- This is the labelled diagram of the longitudinal section of the plant part constituted by M,NO and P parts.
(1) (d) Of M,O and P, which two part are more essential for plant reproduction? Give reasons in favour of you answer.
Answer:- Among M,O and P,M and P parts are more essential for plant reproduction. Because M is the male reproductive organ and P is the female reproductive organ.
(2) (a) What is vegetative reproduction?
Answer:- Asexual reproduction takes place by vegetative structure i.c. Without formation of spore or gamete this type of reproduction is known as vegetative reproduction.
(2) (b) What do you mean by germination?
Answer:- The development of a seeding from a seed is called germination.
(2) (c) Explain pollination between P and Q flower.
Answer:- The pollination between P and Q flowers is known as self pollination. Here, the transfer of pollens from anthers to stigmas happens between flowers on the same plan. (P and Q are the flower on the same plant Q)
(2) (d) Which pollination of the two figures play role in creating new characteristics? Give your comments after having a comparative analysis.
Answer:- The pollination s and R flowers which is known as cross pollination plays role in creating new characteristics. Hera, the pollination happens on another plant of same species. (As the another plant may have different atmosphere, soil than it may have some different characteristics) So when parents are from different plants then the next generation may have some new characteristics.