10 Science Solved Sample Paper 4 – Page 4
Question: 18. (1). Draw a labelled diagram of excretory system in human beings and label the following:
(i) Left kidney; (ii) renal artery; (iii) urinary bladder; (iv) urethra
(2). Name the functional unit of kidney.
(3). Name two nitrogenous wastes released from kidney. [5 marks]
Answer: (2) The functional unit of kidney is Nephron.
(3). These nitrogenous wastes are: Urea and Uric acid.
(1). Draw a diagram of human alimentary canal and label the following parts:
(i). Largest gland.
(ii). gland that secretes digestive enzymes and hormone.
(iii). part where HCI is produced.
(iv). Part where digested food is absorbed.
(2). What are will? Explain their function in the digestive system.
Question: 19. How is a micelle formed in the cleansing action of soap? Explain it with the help of a diagram. Explain the role of micelle in the cleansing process. Soap and detergents, both are same type of salts. How are they chemically different form each other? Explain. 
Question:20. (1). In human male as well as female reproductive systems there is an organ which apart from producing germ-cells, also plays the role of an endocrine gland. Name the organ for each of the reproductive systems. Draw a diagram of female reproductive system and label on it-cervix and vagina.
(2). Name the site of fertilization and also the place where fertilized egg gets imported in female reproductive system.
(3). State the advantage of development of embryo in mother’s womb. 
(1). Organ in male reproductive system – Testis; Organ in female reproductive system – Ovary
(2). Site of fertilisation – Fallopian tube
What is meant by ‘speciation’? List four factors that could lead to speciation. Which of these factor cannot be a major in the speciation of asecually producing organisms? Explain your answer. 
Hint: Speciation is the process of formation of a new species from pre-existing ones.
Four factors: (i). Grnetic Drift, (ii). Natural selection, (iii). Geographical isolation, (iv). Severe changes in DNA/change in number of chromosomes/Mutation.
Question: 21. A person with a myopic eye cannot see clearly the objects placed beyond 1.5 m. Mention two possible reasons due to which this defect may arise. With the help of ray diagrams show:
(1). Why is he unable to see clearly the objects placed beyond 1.5 m from his eye; and
(2). What should be the type of the corrective lens used to restore proper vision and how this effect is corrected by the use of this lens?
(1). (i). Excessive curvature of eye lens; (ii) Elongation of eye ball; Diagram for myopia
(2). Concave lens; Use of concave lens for the correction of defect.