Birds have hollow bones due to the fact thay need to be as light as possible for their wings to generate enough lift for them to fly
The answer to this question is B
Image result for Is work done when you carry a book across the room at a constant velocity
Work is not done when you carry an object forward. You may have learnt that carrying an object and moving horizontally at a constant velocity has no work done. The truth is, there is a slight amount of work done due to overcoming air resistance in the horizontal direction.
Pros (good):
- Inexpensive
- Can degrade the crudest oils
- Quick and minor waste is water and CO2
Cons (bad)
- Waves can carry bacteria into place they are not needed or wanted
- Germs may harm marie animals by putting excess CO2 in water
- Germs may be harder to exterminate because they are engineered
