Which of the following statements is true?
a. calcium and potassium are good for your body.
b. most of the atmosphere is made of oxygen and helium.
c. the center of an atom is made of protons and electrons.
d. all of the above.

Ineed with my science work! it’s due tomorrow!

Melting and boiling are endothermic processes. this means that these processes absorb energy from their surroundings in order to occur. use this information and the data you collected in the phase change gizmo to describe what happens to the temperature of water when you boil it, then explain why this result occurs.

Although respiratory organs vary across different organisms, they all contain respiratory surfaces that have a large surface area and are extremely thin. explain why having an extremely thin respiratory surface with a large surface area is advantageous for the process of gas exchange