Topics on how humans use energy pls can somebody give me a few..

The agent of mechanical weathering in which rock is worn away by the grinding action of other rock particles is call

Citric acid has a ph between 1 and 3.  it is considered to be aa. weak acidb. weak basec. strong based. strong acid

An engineer decides to use a slightly weaker material rather than a stronger material, since she knows that the stronger material can break suddenly. this is an example of what? a choosing a material that will show warning before it fails b using composite materials that combine strength c using a material for multiple applications d using design techniques that increase efficiency and reduce cost