Answer: The number of protons and the number of neutrons determine an element's mass number.
Explanation:
Answer: The bubbles produced are most likely due to oxygen.
Explanation:
Photosynthesis is a phenomenon in which green plants containing chlorophyll use sunlight as a source of energy to convert carbon dioxide and water to form glucose and oxygen.
The balanced chemical reaction for photosynthesis is:

Thus the bubbles produced are most likely due to oxygen.
Answer:
Hydrogen Bond
Explanation:
Hydrogen bond interactions are formed between the hydrogen atom bonded to most electronegative atoms (i.e. F, O and N) of one molecule and most electronegative atom (i.e. F, O and N) of another molecule.
In this interaction the hydrogen atom has partial positive charge and electronegative atom has partial negative charge.
I think the correct answer from the choices listed above is option D. Outer planets are mostly made up of gases and are huge in size. These gases are hydrogen and helium. <span>These outer planets are Saturn, Jupiter, Uranus, and Neptune. Hope this answers the question.</span>