Who is percy jacksons brother need it for my test and thnks

What process is believed to be responsible for the formation of the grand canyon? a) diverging tectonic plates b) converging tectonic plates c) erosion over a long period of time d) caving in of the ground due to erosion

Which of the following entities ensure that national security policies are carried out? check all that apply.

98 points! include an answer and in advance!