As proved by many studies greenhouse effect is rapidly increasing because of increase in concentration of carbon dioxide. In the given graph the increase in carbon dioxide concentration is shown. What could be X corresponding to it?
(i) Rate of photosynthesis in plants
(ii) pH of the oceans
(iii) Water level of ocean
(iv) Average global temperature of Earth
A (i) and (iii) only
B (ii) and (iv) only
C (ii) only
D (iv) only
There should be an option for (ii), (iii),