8. How do Organisms Reproduce Science class 10 in English Medium ncert book solutions Exercise

Exercises:

Q1. Asexual reproduction takes place through budding in
(a) amoeba.
(b) yeast.
(c) plasmodium.
(d) leishmania.

Answer: (b) yeast

Q2. Which of the following is not a part of the female reproductive system in human beings?
(a) Ovary
(b) Uterus
(c) Vas deferens
(d) Fallopian tube

Answer: (c) Vas deferens 

Q3. The anther contains
(a) sepals.
(b) ovules.
(c) carpel.
(d) pollen grains.

Answer: (d) pollen grains. 

Q4. What are the advantages of sexual reproduction over asexual reproduction?

Answer: The advantages of sexual reproduction over asexual reproduction are as follows: 

(i) There are much variations in the organisms reproduced by sexual reproduction than of the asexual reproduction. 

(ii) It plays an important role in speciation. 

(iii) There are much options to combine of new variations of DNA. 

(iv) The new indivisual is differ to parent in physically but similar at DNA level. 

(v) The sexual reproduction encourrages much new features in offspring as it occurs by fission of two difference gamates while there is no so happens in asexual reproduction.   

Q5. What are the functions performed by the testis in human beings?

Answer: Function of testis in human beings:

(i) It produces male gamate sperms. 

(ii) It releases male sex hormone testosterone. 

Q6. Why does menstruation occur?

Answer: A girl with puberty performs menstruation when an egg does not fertilise. After releasing ovum(egg) comes in fallopian tube and if here it comes in the contact of male gamate sperm the fertilisation takes place but if fertilisation does not take place it comes down in the uterus and after 3 to 4 days it gets degenerated and mixed with blood and mucus comes out of uterus. This is called menstruation and it occurs after every 28 days.    

Q7. Draw a labelled diagram of the longitudinal section of a flower.

Answer: 

Q8. What are the different methods of contraception?

Answer: There are following contraception methods: 

(i) Barrier methods - These methods are used outside the body ie on the upper skin eg - condom for male, diaphragm for female. This does not allow the sperm to meet the female's ovum.

(ii) Chemical methods: These methods are used by the female. Females can prevent pregnancy with oral pills. Oral pills especially cause changes in the hormones of the body, but sometimes they also have bad effects.

(iii) Loop or Copper-T: Pregnancy can also be stopped by installing in the uterus.

Q9. How are the modes for reproduction different in unicellular and
multicellular organisms?

Answer: Single-celled organisms have simple structure, so asexual reproduction takes place in them and they do not have special organs for reproduction. There are two types of reproduction in these - double fission and multiple fission. Multicellular organisms have reproductive systems due to complex structures, so sexual reproduction occurs in them as well as asexual.
Q10. How does reproduction help in providing stability to populations of species?

Answer: The basic structure of reproduction makes DNA replication. Cells Different chemical reactions Two copies of DNA are formed, it is responsible for the structure and pattern of the organism, these copies of DNA are separated and 'divided'. and forms two cells. In this way some variation comes which is beneficial for the existence of the species
Q11. What could be the reasons for adopting contraceptive methods?

Answer: Pregnancy devices are adopted to prevent pregnancy. Organisms perform reproductive activity and increase the growth of living beings, thus if this process continues continuously, then the population on the earth explodes, apart from this, there is an adverse effect on the woman's body at the time of conception. So more often this action can be harmful for him. Thus contraceptive devices are absolutely necessary.