PLEASE SOMEONE ANSWER N IGNORR THE HANDWRITING
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not able to understand why don't you type them
Answer: 1. (i)
- The first step in the process of reproduction is the fusion of a sperm and an ovum. When sperms come in contact with an egg, one of the sperms may fuse with the egg. Such fusion of the egg and the sperm is called fertilization.
- During fertilization, the nuclei of the sperm and the egg fuse to form a single nucleus. This results in the formation of a fertilized egg or zygote. The zygote is the beginning of a new individual.
- Fertilization results in the formation of zygote which begins to develop into an embryo. The zygote divides repeatedly to give rise to a ball of cells. The cells then begin to form groups that develop into different tissues and organs of the body. This developing structure is termed an embryo. The embryo gets embedded in the wall of the uterus for further development.
- The embryo continues to develop in the uterus. It gradually develops the body parts such as hands, legs, head, eyes, ears, etc. The stage of the embryo in which all the body parts can be identified is called a foetus. When the development of the foetus is complete, the mother gives birth to the baby.
2.The process of fertilization is the meeting of an egg cell from the mother and a sperm cell from the father. So, the new individual inherits some characteristics from the mother and some from the father.
3. Adolescents should be careful about what they eat because proper diet is needed for the rapid growth taking place in their body. The right meal for adolescents consist of chapatti, dal, vegetables. It is important that the body gets the correct nutrition during adolescence to ensure healthy growth of bones, muscles and other parts.
4. (i) No,i don't agree. All human beings have 23 pairs of chromosomes in the nuclei of their cells. Two chromosomes out of these are the sex chromosomes, named X and Y. A female has two X chromosomes, while a male has one X and one Y chromosome. The gametes (egg and sperm) have only one set of chromosomes. The unfertilised egg always has one X chromosome. But sperms are of two kinds. One kind has an X chromosome, and the other kind has a Y chromosome. When a sperm containing X chromosome fertilises the egg, the zygote would have two X chromosomes and develop into a female child. If the sperm contributes a Y chromosome to the egg (ovum) at fertilisation, the zygote would develop into a male child. This concludes that the sex chromosomes of the father determine the sex of an unborn baby.
(ii) Pituitary gland: It is located in brain. It is also called master gland because it controls like a master and it controls the functioning of other glands. It secretes growth hormones which control the development of bones and muscles. If there is excessive secretion (hyper secretion) of GH it causes gigantism and on the other hand if it secrets less (hypo secretion) it will cause dwarfism.
Adrenal Gland- The word ‘Renal’ is related with kidney. So the adrenal glands are located on top of kidneys which are a cap like structure. They secrete adrenalin that regulates heart beat, breathing rate, blood pressure, etc. So, we can say that adrenalin is a hormone which prepares our body for action as it controls our feelings. It is also known as emergency hormone.
6. CFC and CH₄
7. Jim Corbett National Park.
Explanation: