Class X Chapter 8 – How do Organisms Reproduce Science
Question 8 : What are the different methods of contraception ? Answer : The contraceptive methods can be broadly divided into the following types :
• Natural method→ It involves avoiding the chances of meeting of sperms and ovum . In this method , the sexual act is avoided from day 10th to 17th of the menstrual cycle because during this period , ovulation is expected and therefore , the chances of fertilization are very high .
• Barrier method → In this method , the fertilization of ovum and sperm is prevented with the help of barriers . Barriers are available for both males and females . Condoms are barriers made of thin rubber that are used to cover penis in males and vagina in females .
• Oral contraceptives →In this method , tablets or drugs are taken orally . These contain small doses of hormones that prevent the release of eggs and thus fertilization cannot occur .
• Implants and surgical methods →Contraceptive devices such as the loop or Copper-T are placed in uterus to prevent pregnancy . Some surgical methods can also be used to block the gamete transfer . It includes the blocking of vas deferens to prevent the transfer of sperms known as vasectomy . Similarly , fallopian tubes of the female can be blocked so that the egg will not reach the uterus known as tubectomy .
Question 9 : How are the modes for reproduction different in unicellular and multicellular organisms ? Answer : In unicellular organisms , reproduction occurs by the division of the entire cell . The modes of reproduction in unicellular organisms can be fission , budding , etc . whereas in multicellular organisms , specialised reproductive organs are present . Therefore , they can reproduce by complex reproductive methods such as vegetative propagation , spore formation , etc . In more complex multicellular organisms such as human beings and plants , the mode of reproduction is sexual reproduction . Question 10 : How does reproduction help in providing stability to populations of species ?
Page 8 of 9