Questions

Africa is the second largest continent both by popolation and area wise. Asia being first by both popolation and area wise.

Carbohydrates, together with lipids, proteins and nucleic acids, are one of the four major classes of biologically essential organic molecules found in all living organisms. They not only provide energy for vital metabolic reactions but also supply the building materials for normal structure, growth and repair. Your body needs relatively large quantities of carbohydrates, fats and protein for optimal function, hence their classification as macronutrients.

At least one black can be chosen in two ways from each box:
Now, probability of choosing at least one black ball from first box 

= 1/2 × [ (2C1× 2C1)/4C2 + 2C2/ 4C2 ]= 5/12

Probability of choosing at least one black ball from 2nd box
= 1/2 × [(4C1×12C1)/16C2 + 4C2/ 16C2] = 9/40

Final probability

= 5/12 + 9/40 = (50 + 27)/120 = 77/120

Ethylene is used for Artificial Ripening of Green Fruit.

• Calcium carbide is also used in some countries for artificially ripening fruit. When calcium carbide comes in contact with moisture, it produces acetylene gas, which is quite similar in its effects to the natural ripening agent, ethylene