70. (i) Oxygen given out during photosynthesis comes from water.   71. (ii) The need to limit the size of family is more vital today than ever before. Give two reasons.   72. (iii) Root hairs becomes flaccid, when fertilizer are added to the moist soil around it.   73. (iv) Transplanting of seedlings to a flower bed in the evening is better than doing so in the morning.   74. (v) In summer urine is slightly thicker than in winter.   75. (vi) The man can live without food for a number of days but he can not survive without Oxygen for more than a few minutes.   76. (vii) Environmental pollution is a recent problem. Do you agree? Give two reasons to support your answer.