Questions

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.

The Coconut tree

A device which is used to convert light energy directly into electrical energy is called as photovoltaic cell or a solar cell.

Heliostats convert light energy into heat energy.

A thermocouple is a device for measuring temperature.

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

Natural selection is the differential survival and reproduction of individuals due to differences in phenotype. It is a key mechanism of evolution, the change in the heritable traits characteristic of a population over generations.