In converting a number with the unit of meter into kilometer we must use the conversion factor 1 km per 1000 meters.This is because in 1 kilometer there are 1000 meters and then the unit to be converted is already in meter so we need to divide it for us to convert.
Permitting the exchange of nutrients and gases between the blood and tissue cells is the primary function of capillaries. Capillaries are the smallest blood vessels , they are only one cell thick, and they act as sites of the transfer of oxygen and other nutrients from the bloodstream to the body tissues. Additionally, they also collect carbon dioxide, waste materials and fluids for return to the veins.