Fume hoods are used to a. prevent fires from spreading in the lab b. put out fires c. prevent toxic gases from spreading through the lab d. clean chemicals off the body

c. prevent toxic gases from spreading through the lab

A fume hood is also called as fume cupboard. It is a ventilation device. It is installed in the laboratory to absorb the hazardous toxic fumes liberated during chemical reactions. The spreading of the chemical fumes generated during chemical experiment can cause accidents like fires, explosion, inhalation of fumes can cause respiratory problems in humans and can also be lethal. Therefore, fume hood should be installed in the laboratory.

answer:

the water molecules are transferred from the roots to the stem or top parts of the tall tree because of important properties of water which are adhesion, cohesion and capillary action. cohesion is the property of water molecules keeps water molecules in a combined state by sharing of bonds between them at the atomic level. adhesion allows the interaction of water molecules with other substances or substrate. adhesion will cause the attachment of water molecules to the wall of the vessel (xylem) of the plant. capillary action occurs when the adhesive force to the vessel wall is stronger than the cohesive force between water molecules. capillary action mimics the transfer of water from a tube or pipe. in this way water utilizes its property to transfer water from down to top level of the plant.  

it's diluted or concentrated

in a diluted solution, you can add a lot more solute but in concentrated only a little more can be added