Long Answer TypeThe diagram given alongside is the external view of the human brain. Study the same and answer the questions that follow:
(i) Name the parts labelled 1,2 and 3.
(ii) State the main functions of the parts labelled 1 and 2.
(iii) How are the brain cells arranged in the part labelled ‘1’?
(iv) What is the structural and functional unit of the nervous system?
(v) Name the fluid that surrounds the brain. State its function.Explain briefly .
(i) There is an increasing dependence today on natural sources of energy like sunlight and wind.
(ii) The breathing rate increases after vigorous exercise.
(iii) On entering a poorly lit room, one feels blinded for a short while.
(iv) Glucose is normally not found in urine.
(v) Xerophytes have their leaves modified to spines or reduced in size.(i) There is an increasing dependence today on natural sources of energy like sunlight and wind because:
1. Until modern days, all energy was derived from fossil fuels like coal and petroleum, which are now limited and non-renewable.
2. Natural sources of energy like sunlight and wind are unlimited and renewable.
(ii) The breathing rate increases after vigorous exercise because the energy of the tissues is consumed during this process.Thus, the breathing rate increases to allow more oxygen to reach the tissues for the production of energy.
(iii) On entering a poorly lit room, one feels blinded for a short while because in bright light the rods cells of the eye are bleached and take some time for the regenration process. Moreover, the pupils were constricted due to bright light to let in less light and thus one feels blinded.
(iv) Glucose is normally not found in urine because the hormone insulin in our body converts the excess glucose into glycogen, which is then stored in the liver.
(v) Xerophytes have their leaves modified to spines or reduced in size to decrease the loss of water by transpiration.
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