The colours of fridges preferred by people living in a locality are shown by the following pictograph

It has been found that people living in very high mountains have many more red corpuscles in their blood than people living in plains. Which one of the following best accounts for this phenomenon ?

Why does frog prefer in live in or near water ?

Total number of students of a school in different years is shown in the following table. Prepare another pictograph of students using any other symbol each representing 50 students. Which pictograph do you find more informative ?