which statements are true? select all that apply.
a. an atom is the smallest complete part of an element.
b. an element is a pure substance made of one kind of atom.
c. the nucleus is the tiny center of an atom, and it contains protons and neutrons.
d. isotopes are atoms of the same element that contain the same number of neutrons but different numbers of protons.

Aplane cuts a pyramid as shown in the diagram. what is the shape of the cross section? a. a hexagon b. a pentagon c. a square d. a triangle

What is likely to happen in the long term if the earth continues to absorb more energy than it emits? a. the earth will discontinue recycling energy. b. organisms will begin to compensate for the change by incorporating more energy. c. the overall temperature of the earth will increase. d. the nutrient cycles will happen more frequently. select the best answer from the choices provided a b c d

What is the only country that borders portugal