A person who balances all the three healths such as Physical, mental and Social healths has the best overall health.

Excretion is best described as the removal of Metabolic wastes from a cell.

An Element is a pure substance of one type of atom. In chemistry, any material such as carbon, hydrogen, iron, or oxygen that cannot be broken down into more fundamental substances is nothing but an element.

During convection, cool and dense air falls through the warmer and less dense air. The warm air having less mass is being displaced by the cooler which is much heavy. Convection always involves the air rising through the atmosphere.

Pollination is when pollen grains from an anther, the male portion of a flower, are transferred to a female part of the flower, known as the stigma. In order for pollination to be successful, the pollen grains transferred must be from a flower of the same species.

After the pollen grains land on the stigma, they create a pollen tube through the length of the style or stalk connecting the stigma and ovary. Once the pollen tube is complete, the pollen grain will send sperm cells from the grain down to the ovary. When the sperm cells reach the ovary and the egg cells, fertilization will occur, which will result in the formation of the seed. The seed will then be released from the parent plant and will be able to grow into a plant and continue the reproductive cycle using the method of pollination.

PRINCE.

Because arteries have to have thick walls for use of protection. Its when you get to veins where the walls get thinner. And the use of the heart is to pump blood to all of the cells and organs in the body so it would be to transport blood away from the heart.

i.e. 

Arteries = Away from the Heart 
Veins = Back to the Heart.

silver is the best conductor of electricity.

When compared to remaining 3 metals, as Silver having more number of free electrons in its valency shell it is the good conductor of electricity.

Conductors Thermal Conductivity @ 25degree C

Silver --- 429
Copper --- 401
Gold --- 310
Aluminium --- 250