NCERT Solutions Class 12 Biology Chapter 4

Q.1 What do you think is the significance of reproductive health in a society?

Ans-

According to World Health Organization, health means a state total well-being in all the aspects like: physical, emotional, behavioural and social. A society with people having physically and functionally normal reproductive organs with normal interactions among them in all sex-related aspects is called reproductively healthy society. The importance of reproductive health is as follows:

1. The offspring of healthy parents will be healthy, thus the overall health of society will be good, in all aspects of life.
2. Proper information about reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases (STDs), etc., will help people lead a healthy life.
3. A reproductively healthy society will have correct information about pregnancy, child-birth and post-natal care. This will keep the mother and the child lead healthy and happy life. Such societies will well address the problems of uncontrolled population growth, sex-abuse and sex-related crime, etc.

Q.2 Suggest the aspects of reproductive health which need to be given special attention in the present scenario.

Ans-

Aspects of reproductive health which need to be given special attention in the present day scenario are:

• Proper information about reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases (STD), etc., so that people can lead a normal and healthy life.
• Sex education in schools should be made compulsory to help children understand the right facts about sexual practices and reproduction.
• Proper information should be made available to fertile couples and people in marriageable age group about available birth control options, care of pregnant mothers, post-natal care of the mother and child, the importance of breastfeeding, etc., for the well-being of mother and child.
• Society needs to be educated about the importance of bringing up a male and female child with equal opportunities so that female foeticide can be curbed.
• People should be made aware of the problems society faces when there is uncontrolled population growth resulting in social evils like sex-abuse and sex-related crime.

Q.3 Is sex education necessary in schools? Why?

Ans-

Sex education is very important in schools as it provides the youngsters correct knowledge about various aspects of reproductive health like: reproductive organs, adolescence and related changes, safe and hygienic sexual practices, sexually transmitted diseases (STDs), etc. This would not just help them lead a normal healthy life, but also protect them from acquiring STDs and stay protected from sex abuse and sex-related crimes. The right information would discourage children from believing in myths and having misconceptions about sex-related aspects. This would help create a sexually conscious and healthy society.

Q.4 Do you think that reproductive health in our country has improved in the past 50 years? If yes, mention some such areas of improvement.

Ans-

Yes, reproductive health in our country has improved in the past 50 years. This has been made possible by the successful implementation of various action plans, strong infrastructural facilities, professional expertise and material support. Some such areas of improvements are as follows:

1. A statutory ban on amniocentesis (chromosome-based sex determination test) has resulted in a decline in female foeticide.
2. Good medical assistance and care with better techniques and new strategies have helped overcome reproduction-related problems like pregnancy, delivery, STDs, abortion, contraception, infertility, etc. to a large extent. These steps have resulted in the rapid decline of maternal mortality and infant mortality rate.
3. Massive child immunisation program has also been another successful program that has resulted in decreased infant deaths and healthy children.
4. Large scale use of contraceptive methods due to massive awareness programmes and their easy availability have resulted in smaller families, thus checking the population growth.

Q.5 What are the suggested reasons for population explosion?

Ans-

When the number of people in a group exceed the carrying capacity of the region due to rapid increase of a population it is called population explosion. Population of most of the developing countries has drastically increased. According to an estimate, by 2050 the world’s population will be between 7.9 billion and 10.9 billion. If this trend continues, very soon there will be massive scarcity of basic requirements like food, shelter, clothing, etc. Some of the suggested reasons for this population explosion have been all-round development and successful implementation of programs in various fields of reproductive health. Awareness and availability of better health facilities along with better living conditions are one of the major reasons for population explosion. A rapid decline in death rate, maternal mortality rate and infant mortality rate as well as increase in number of people in reproductive age are some other major reasons for an alarming increase in population.

Q.6 Is the use of contraceptives justified? Give reasons.

Ans-

Contraceptives are devices, drugs, agents, sexual practices, or surgical procedures that prevent conception or pregnancy. Contraception helps women plan if and when they want to conceive. The use of contraceptives is very much justifiable due to the following reasons:

1. It helps in checking population growth.
2. Couples can plan when they want to have children and how many, without affecting their married life.
3. Contraceptives prevent unwanted pregnancies and spread of sexually transmitted diseases (STDs).

Q.7 Removal of gonads cannot be considered as contraceptive option. Why?

Ans-

Contraceptive methods should be user-friendly, easily available, effective and reversible with no or least side effects. Removal of gonads cannot be considered as contraceptive option because of following reasons:

1. Complete removal of gonads will not just result in infertility, but will also devoid body of the hormones, released from these organs, which are important for normal functioning of other organs.
2. This is an irreversible process and thus, couple can never conceive again after gonads are removed.

Q.8 Amniocentesis for sex determination is banned in our country. Is this ban necessary? Comment.

Ans-

Amniocentesis is a medical process in which a long needle is passed through the abdominal wall of the pregnant mother to withdraw a small amount of amniotic fluid along with foetal cells. These cells are used for karyotyping to detect any kind of chromosomal abnormality. The main application of the technique is in pre-natal diagnosis of chromosomal abnormalities and can be carried out after 16^th week of pregnancy. Karyotyping not just gives information about the autosomal chromosomes, but also about sex chromosomes and thus, sex of the foetus can be determined through amniocentesis. In many places across India, birth of girl child is not desirable for various socio-economic reasons. Thus, people do not want a girl child. Therefore, they go for tests, like amniocentesis to find out the sex of the foetus. If they find that the foetus is a female child, they go for abortion. This is an illegal practice and leads to skewed male:female ratio in the society. In order to curb this, amniocentesis for sex determination has been banned in our country.

Q.9 Suggest some methods to assist infertile couples to have children.

Ans-

Couples who are unable to conceive in spite of unprotected sexual intercourse are infertile couples. Many reasons contribute to infertility, for example, physical environment, congenital diseases, drugs and immunological health. In some cases, special techniques known as assisted reproductive technologies (ART) play a very important role in treating infertile couples. Various ART are as follows:

1. In-vitro fertilisation or test-tube baby followed by ‘Embryo transfer’ (ET): This is a technique by which fertilisation is carried out outside the body under conditions similar to those inside the body. Ova from the wife/donor (female) and sperms from the husband/donor (male) are collected and induced to form zygote under ideal lab conditions. The zygote or early embryo (upto 8 blastomeres) is then transferred into the fallopian tube (ZIFT – zygote intra fallopian transfer) and embryos with more than 8 blastomeres are transferred into the uterus (IUT-intra uterine transfer) to complete its further development.
2. Gamete intra fallopian transfer (GIFT): In this method, ovum is collected from a donor (female) and transferred into the fallopian tube of another female who cannot produce one, but can provide the right environment for fertilisation and further development of the embryo.
3. Intra cytoplasmic sperm injection (ICSI): This is another very specialised technique where sperm is directly injected into the ovum under laboratory conditions.
4. Artificial insemination (AI): The semen collected either from the husband or a healthy donor is artificially introduced either into the vagina or into the uterus of the female. This technique is useful in those cases where the sperm count in semen is either very low or male partner cannot inseminate.

Q.10 What are the measures one has to take to prevent from contracting STDs?

Ans-

Sexually transmitted diseases (STDs) are diseases or infections which are transmitted through sexual intercourse and are caused by viruses and bacteria. Humans do not have a good level of immunity to any of the STDs. Early symptoms are mild but if left untreated, they result in serious complications later. Thus, STDs are a major threat to a healthy society. Prevention is the best cure for not contracting STDs. Some simple measures that should be taken to prevent STDs are as follows:

1. Information and knowledge of the facts related to STDs.
2. Avoiding sex with unknown partners or multiple partners.
3. Using condoms during coitus (intercourse).
4. Immediately visiting a qualified doctor for early detection and taking complete treatment if diagnosed with the disease.

Q.11 State True/False with explanation
(a) Abortions could happen spontaneously too. (True/False)
(b) Infertility is defined as the inability to produce a viable offspring and is always due to abnormalities/defects in the female partner. (True/False)
(c) Complete lactation could help as a natural method of contraception. (True/False)
(d) Creating awareness about sex related aspects is an effective method to improve reproductive health of the people. (True/False)

Ans-

(a) True

Explanation: Abortion is the termination of pregnancy by the removal or expulsion of a foetus or embryo from the uterus before the time of parturation. It can be spontaneous also, called miscarriage. Miscarriage mostly occurs due to chromosomal problems which make it impossible for the foetus to develop. Other possible causes of miscarriage may be drug and alcohol abuse, exposure to environmental toxins, hormone-related problems, infections, obesity, physical problems with mother’s reproductive organs, etc.

(b) False

Explanation: Infertility is defined as the inability to produce a viable offspring inspite of unprotected sexual intercourse. There can be many reasons for infertility such as physical abnormalities, congenital diseases, side-effect of drugs, weak immune system and psychological well being.

(c) True

Explanation: Complete lactation could help as a natural method of contraception however, it is effective only upto a maximum period of six months following parturition or child birth. This is based on the fact that ovulation and therefore menstrual cycle, do not occur during the period of intense lactation (first six months) following childbirth. Thus, it is said that as long as mother breast feeds the child completely, chances of conception are nil. However, the chances of failure of this method are also very high.

(d) True

Explanation: Reproductive health means total well-being in all the aspects of reproduction, e.g. physical, emotional, behavioural and social. Thus, a society with people who are well informed about the merits and demerits of sex-related issues will behave in accordance with it and thus; will remain healthy.

Q.12 Correct the following statements:
(a) Surgical methods of contraception prevent gamete formation.
(b) All sexually transmitted diseases are completely curable.
(c) Oral pills are very popular contraceptives among rural women.
(d) In E.T. technique, embryos are always transferred into the uterus.

Ans-

(a) Surgical methods of contraception do not prevent gamete formation. Instead, they block gamete transport and thereby prevent conception. In males, it is called ‘vasectomy’ (a small part of the vas deferens is cut and tied up through a small incision on the scrotum) whereas, it is called ‘tubectomy’ in females (a small part of the fallopian tube is cut and tied up through a small incision in the abdomen or through vagina).

(b) All sexually transmitted diseases are not completely curable. Except for hepatitis-B, genital herpes and HIV infections, all other STDs are completely curable if detected early and treated properly. Medical advancements have still not found a complete cure for hepatitis-B, genital herpes and HIV infections.

(c) Oral pills are not very popular contraceptives among rural women. Intra Uterine Devices (IUDs) are one of the most widely accepted methods of contraception in India. These devices are inserted by medically trained personnel in the uterus through the vagina. They work by either increasing phagocytosis of sperms within the uterus, by releasing the Cu (Copper) ions that suppress motility and viability of sperms, or by releasing hormones that make the uterus unsuitable for implantation.

(d) In embryo transfer (E.T.) technique, embryos are not always transferred into the uterus. Ova from the wife/donor (female) and sperms from the husband/donor (male) are collected and induced to form zygote under ideal lab conditions. The zygote or early embryo (with upto 8 blastomeres) is then transferred into the fallopian tube (ZIFT – zygote intra-fallopian transfer) and embryos with more than 8 blastomeres are transferred into the uterus (IUT-intra uterine transfer) for its further development.