Answer:
due to ageing the physical senses and properties like eye's power become weak and slowly it starts to work weak in old people.
Umm.. Planting trees gives us more trees...we need trees because they provide oxygen,food(some trees), resources(such as paper), homes for animal(where eles will the squirrel live).
You need more context to answer this.
It is true because scientists often do that
A the flowering of the four oclock plant at the same time
