Investigating which question will help a student find out whether the core of Mars is similar to the core of Earth?
Is the core of Mars metallic?
O What is the rate of rotation of the core of Mars?
O Is the core of Mars thicker than other layers of Mars?
Does the core of Mars have a strong gravitational field?

i think the answer is

mass

answer; polycythemia is the correct answer;

i know can you plzz me with this question im sorry i didt answer your question i just need hel.

hydrogen is a compound or a single element and a element is a pure substence that cannot be separated into simpler subtances

clorine is a compound its a chemical substance that forms when two or more different elements combine

so both hydrogen and clorine are compounds