10th
- Why are traits acquired during the life-time of an individual not inherited? This happens because an acquired trait involves change in non-reproductive tissues which cannot be passed on to germ cells or the progeny. T... 1
- What are the different ways in which individuals with a particular trait may increase in a population? Individuals with a particular trait may increase in a population as a result of the following: Natural selection: When that trait offers som... 2
- How is the sex of the child determined in human beings? In human beings, the females have two X chromosomes and the males have one X and one Y chromosome. Therefore, the females are XX and the mal... 1
- A man with blood group A marries a woman with blood group O and their daughter has blood group O. No. This information is not sufficient to determine which of the traits - blood group A or O - is dominant. This is because we do not know a... 1
- How do Mendel's experiments show that traits are inherited independently? Mendel crossed pure breeding tall plants having round seeds with pure breeding short plants having wrinkled seeds. The plants of F_(1 )gener... 1
- How do Mendel's experiments show that traits may be dominant or recessive? The trait which appears in all the members of F_(1 )generation and also in 75% numbers of F₂ generation obtained by self fertilization of F₁... 1
- How does the creation of variations in a species promote survival? Variations occur due to sexual reproduction and also due to inaccurate copying of DNA. Depending on the nature of variations, different indi... 1
- If a trait A exists in 10% of a population of an asexually reproducing species and a trait B exists in 60% of the same Trait B because in asexual reproduction traits which are present in the previous generation are carried over to next generation with minimal... 1
- What could be the reasons for adopting contraceptive methods? Contraceptive methods are mainly adopted because of the following reasons: To prevent unwanted pregnancies. To control population rise or bi... 1
- How does reproduction help in providing stability to populations of species? Reproduction is the process of producing new individuals of the same species by existing organisms of a species, so, it helps in providing s... 1
- How are the modes for reproduction different in unicellular and multicellular organisms? In unicellular organisms, reproduction occurs by the division of the entire cell. The modes of reproduction in unicellular organisms can be... 1
- What are the different methods of contraception? The contraceptive methods can be broadly divided into the following types: Natural method: It involves avoiding the chances of meeting of sp... 1
- Draw a labelled diagram of the longitudinal section of a flower. Read the text in diagram :: 1
- Why does menstruation occur? Menstruation is a process in which blood and mucous flows out every month through the vagina. This process occurs every month because one eg... 1
- What are the functions performed by the testis in human beings? Functions of testes: Produce sperms, which contain haploid set of chromosomes of father. Produce a hormone called testosterone, which brings... 1
- What are the advantages of sexual reproduction over asexual reproduction? Advantages of sexual reproduction: In sexual reproduction, more variations are produced. Thus, it ensures survival of species in a populatio... 1
- The anther contains (a) sepals. (b) ovules. (c) carpel. (d) pollen grains. Correct option is d) pollen grains. The anther contains pollen grains. 1
- Which of the following is not a part of the female reproductive system in human beings ? Correct option is c) Vas deferens Vas deferens is not a part of the female reproductive system in human beings . 1
- Asexual reproduction takes place through budding in (a) amoeba. (b) yeast. (c) plasmodium. (d) leishmania. Correct option is b) yeast Asexual reproduction takes place through budding in yeast 1
- If a woman is using a copper-T, will it help in protecting her from sexually transmitted diseases? No, because copper-T will not prevent contact body fluids. Thus it will not protect her from sexually transmitted diseases. 1
- How does the embryo get nourishment inside the mother's body? After fertilization the lining of uterus thickens and is richly supplied with blood to nourish the growing embryo. The embryo gets nutrition... 1
- What are the changes seen in girls at the time of puberty? The changes seen in girls at the time of puberty are: Increase in breast size and darkening of skin of the nipples present at the tips of th... 1
- What is the role of the seminal vesicles and the prostate gland? The secretions from seminal vesicles and prostate glands lubricate the sperms and provide a fluid medium for easy transport of sperms. Their... 1
- How is the process of pollination different from fertilization? Pollination is the process of transfer of pollens from anther to stigma. It occurs with the help of certain pollinators such as air, water,... 1