Q15. Explain the social implications of AIDS and other Sexually Transmitted Diseases. (STD’s). Answer: AIDS AIDS is a sexually transmitted disease and transmitted through sexual act. AIDS stands for Acquired Immuno Deficiency Syndrome. It is caused by Human Immuno Deficiency Virus (HIV). The virus destroys white blood cells which results in the loss of resistance against …
Q.14 Describe Growth in Human populai tion and its consequence. Answer: Pakistan’s Population Pakistan’s population in the year 2007-08 was 163,775,000. By the end of this decade, our population is expected to exceed 176 million.” High growth rate in past Pakistan’s population had relatively high growth rate in past. When population exceeds th carrying capacity of …
Q.14 Describe Growth in Human populai tion and its consequence. Read More »
Q.13 Explain reproduction in Rabbit. Answer: Rabbits are small mammals found in several parts of the world. Male reproductive system The male reproductive system of rabbit consists of: i) A pair of testes ii) Associated ducts. iii) Glands Testes produce sperms, ducts transport these sperms to external genitalia and glands add secretions to sperms. (1) …
Q.12 Define fertilization and explain its types. Fertilization Answer: After the formation of gametes; fertilization occurs. There are two ineca. hanisms by which fertilization can take place: (1) External fertilization: Introduction In external fertilization, egg cells are fertilized outside the body. Explanation It occurs in aquatic environment and both the male and female animals release their …
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Q11. What is gametogenesis? Explain the spermatogenesis and oogenesis in detail. Definition The formation of gametes is called gametogenesis. Explanation During gametogenesis, diploid (2N) gamete mother cells undergo meiosis and form haploid (1N) gametes. The male and female gametes are formed in specialized organs called gonads. Male Gonads Male gonads are called testes and the production …
Q11. What is gametogenesis? Explain the spermatogenesis and oogenesis in detail. Read More »
Q10. Describe the conditions for seed germination. Answer: External conditions The most important external conditions include water, oxygen and favourable temperature. Water (moisture) Seeds of most plants have low water content, and germination cannot occur until seed coat or other tissues have imbibed water. The absorbed water is used in the digestion of stored food and …
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Q9. Explain the germination of seed. Answer: Definition Seed germination is a process by which a seed embryo develops into a seedling. Process of germination During germination, the embryo soaks up water which causes it to swell, splitting the seed coat. Root is the first structure that emerges from the radicle present in seed. It grows …
Q8. Explain the development and structure of seed. Introduction After fertilization in female gametophyte, zygote divides repeatedly by mitosis and develops into an embryo. At this stage, ovule changes into seed and this completes process of sexual reproduction in plants. Structure of seed It consists of three parts 1. Embryo formed from zygote. 2. Endosperm tissue …
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Q.7 Describe the structural adaptations of insect pollinated and wind pollinated flowers. Answer: The insect pollinated and wind pollinated flowers have structural adaptations that facilitate the transfer of pollen grains between two plants. Some of these adaptations are described below:
Q6. What is pollination? Write its types. Answer: Pollination. The transfer of the pollen grains from flower anther to stigma is called pollination. Types of Pollination There are two types of pollination: (i) Self pollination : The transfer of pollen grains from the anther to the stigma of same flower or other flower of same plant …