1. Q61 What are electropositive atoms ? How does electropositivity vary along the period in the modern periodic table?
  2. Q62 Give reason for the following. Ionic compounds have a high melting point and boiling point.
  3. Q63 What is meant by pollination ? Name and differentiate between the two types of pollination.
  4. Q64 Write the main function of the sensory neuron?
  5. Q65 Why are traits acquired during the lifetime of an individual not inherited?
  6. Q66 What is meant by saying that the potential difference between two points is 1 V?
  7. Q67 Mention the respiratory unit of lungs and excretory unit of kidneys.
  8. Q68 Major amount of water is selectively reabsorbed by the tubular part of nephron in humans. What are the factors on which the amount of water reabsorbed depends?
  9. Q69 What is the cause of dispersion of light on passing through a prism?
  10. Q70 Why is the Government of India imposing a ban on the use of polythene bags ? Suggest two alternatives to use these bags and explain how this ban is likely to improve the environment.