Question : The rapidly growing mass of phytoplankton covering the surface water of a lake or pond is known as:

Option 1: eutrophication

Option 2: water bloom

Option 3: water pollution

Option 4: water hyacinth

Question : Directions: In a certain code language, if sky is known as earth, earth is known as water, water is known as air, air is known as light, and light is known as sound, then what is it that humans breathe in?

Option 1: Air

Option 2: Earth

Option 3: Light

Option 4: Water

Question : The angle of elevation of an aeroplane as observed from a point 30 metres above the transparent water surface of a lake is 30° and the angle of the depression of the image of the aeroplane in the water of the lake is 60°. The height of the aeroplane from the water surface of the lake is:

Option 1: 60 metres

Option 2: 45 metres

Option 3: 50 metres

Option 4: 75 metres