Seminiferous tubules is where the perm is created
The term "hydrophillic" literally means water loving.
Hydrophillic substances are those that have an affinity of water, meaning they are easily dissolved and absorbed in water. Polar substances, those which have charges on the atoms of their molecules, tend to be hydrophillic due to the fact that water itself is a polar substance.
Ash can be harmful to an environment. It mostly depends on how much ash there is though. If a volcano erupted such as Mt. St. Helen's then yes that can harm an environment. Ash can cover the sky and block out the sun for days before disappearing and that will affect the life of plants
Growing willow for biofuel is sustainable development because it is a source of fuel which potentially will never run out. For every willow tree that is cut down, another can be planted in its place. This means that the source of fuel is potentially limitless and subsequently sustainable.