What do most igneous, sedimentary and
metamorphic rocks have in common?
(1) They are formed from molten material.
(2) They are produced by heat and pressure.
(3) They are composed mostly of minerals.
(4) They are found mostly in distinct layers.

i confess that there are several parts of this constitution which i do not at present approve, but i am not sure i shall never approve them: for having lived long, i have experienced many instances of being obliged by better information or fuller consideration, to change opinions even on important subjects, which i once thought right, but found to be otherwise. it is therefore that the older i grow, the more apt i am to doubt my own judgment, and to pay more respect to the judgment of others.

1. where does the energy of a nuclear power plant come from?

d) political bosses should not hold office