Fill in the blanks.
(i) The blood from the heart is transported to all parts of the body by the.
(ii) Haemoglobin is present in cells.
(iii) Arteries and veins are joined by a network of .
(iv) The rhythmic expansion and contraction of the heart is called.
(v) The main excretory product in human beings is.
(vi) Sweat contains water and.
(vii) Kidneys eliminate the waste materials in the liquid form called.
(viii) Water reaches great heights in the trees because of suction pull caused by .
(i) Arteries Arteries have a thick, elastic layer to allow stretching and absorb pressure; it maintains the pressure in the circulatory system. The blood from the heart is transported to all parts of the body by the arteries and the arterioles. The arteries are the blood vessels that carry oxygenated blood from the heart to the tissues of the body through the capillaries.
(ii) Red blood Red blood cells are red in colour due to the presence of red pigment which is known as haemoglobin. Red blood cells carries oxygen from the lungs to all the cells of the body.
(iii) Capillaries Capillaries are the extremely narrow blood vessels (less than 1mm long) which connect arteries to veins and are present in all regions of the body. Capillaries are also known as ‘blood capillaries. Usually blood passes from the heart in the sequence through arteries, arterioles, capillaries, venules and veins and then get back to the heart.
(iv) Heartbeat The spontaneous rhythmic contraction and relaxation of the heart to pump out and receive the blood to and from the body and completes one cycle of it, is called a heartbeat. The heart beats about 72 times in a minute that can be counted easily by counting the pulses.
(v) Urea Urea is a major waste product that is produced in our body. It is excreted through the urine is the major function of the kidney.
(vi) Salts Sweat contains water and salts, and a little of urea and which is removed from the body by sweat glands through the skin.
(vii) Urine The urea and other unwanted salts dissolve in water in the body to form a yellowish liquid waste of which excretion is important; called urine. For the production of urine, nephrons and collecting ducts performs three processes: glomerular filteration, tubular reabsorption and tubular secretion.
(viii) Transpiration Transpiration is the loss of water from the aerial parts of the plants like leaves in the water vapours form; and this occurs through the stomata, cuticle or lenticels of the plants which is known as stomatal, cuticle and lenticels transpiration respectively.
What are stomata? Give two functions of stomata.
Draw a diagram of the human excretory system and label the various parts.
Match structures given in Column I with functions given in Column II.
Column I Column II
(i) Stomata (a) Absorption of water
(ii) Xylem (b) Transpiration
(iii) Root hairs (c) Transport of food
(iv) Phloem (d) Transport of water
(e) Synthesis of carbohydrates
Describe the function of the heart.
Does transpiration serve any useful function in the plants? Explain.
What are the components of blood?
Why is transport of materials necessary in a plant or in an animal? Explain.
Why is it necessary to excrete waste products?
What will happen if there are no platelets in the blood?
Why is blood needed by all the parts of a body?
State similarities and differences between the laboratory thermometer and the clinical thermometer.
State differences between acids and bases.
Classify the changes involved in the following processes as physical or chemical changes:
(a) Photosynthesis
(b) Dissolving sugar in water
(c) Burning of coal
(d) Melting of wax
(e) Beating aluminium to make aluminium foil
(f ) Digestion of food
Name the elements that determine the weather of a place.
Fill the missing word in the blank spaces in the following statements:
(a) Wind is——————air.
(b) Winds are generated due to —————— heating on the earth.
(c) Near the earth’s surface __________air rises up whereas ___________ air comes down.
(d) Air moves from a region of ——— pressure to a region of ———.
In addition to the rock particles, the soil contains
(i) air and water
(ii) water and plants
(iii) minerals, organic matter, air and water
(iv) water, air and plants
Why does an athlete breathe faster and deeper than usual after finishing the race?
Fill in the blanks:
(a) Production of new individuals from the vegetative part of parent is called_____________.
(b) A flower may have either male or female reproductive parts. Such a flower is called_____________.
(c) The transfer of pollen grains from the anther to the stigma of the same or of another flower of the same kind is known as _____________.
(d) The fusion of male and female gametes is termed as _____________.
(e) Seed dispersal takes place by means of _____________, _____________ and _____________.
Classify the following as motion along a straight line, circular or oscillatory motion:
(i) Motion of your hands while running.
(ii) Motion of a horse pulling a cart on a straight road.
(iii) Motion of a child in a merry-go-round.
(iv) Motion of a child on a see-saw.
(v) Motion of the hammer of an electric bell.
(vi) Motion of a train on a straight bridge.
Why do organisms need to take food?
What is sewage? Explain why it is harmful to discharge untreated sewage into rivers or seas.
Mark ‘T’ if the statement is true and ‘F’ if it is false:
(a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)
Fill in the blanks:
(a) An image that cannot be obtained on a screen is called ____________.
(b) Image formed by a convex __________ is always virtual and smaller in size.
(c) An image formed by a __________ mirror is always of the same size as that of the object.
(d) An image which can be obtained on a screen is called a _________ image.
(e) An image formed by a concave ___________ cannot be obtained on a screen.
Name two chemicals used to disinfect water.
Untreated human excreta is a health hazard. Explain.
Why should we worry about the conditions and issues related to forests far from us?
Give one use each of a concave and a convex mirror.
State two experiences that made you think that air exerts pressure (other than those given in the text).
Given below is a square of letters in which are hidden different words related to respiration in organisms. These words may be present in any direction ó upwards, downwards, or along the diagonals. Find the words for your respiratory system. Clues about those words are given below the square.
(i) The air tubes of insects
(ii) Skeletal structures surrounding chest cavity
(iii) Muscular floor of chest cavity
(iv) Tiny pores on the surface of leaf
(v) Small openings on the sides of the body of an insect
(vi) The respiratory organs of human beings
(vii) The openings through which we inhale
(viii) An anaerobic organism
(ix) An organism with tracheal system
Match the following :
(i) Land breeze blows during (a) summer
(ii) Sea breeze blows during (b) winter
(iii) Dark coloured clothes are preferred during (c) day
(iv) Light coloured clothes are preferred during (d) night