Answer:
D. They form an ionic compound.
Explanation:
The bonds which are produced between a metal ion and a non-metal ion are termed as ionic bonds.
Answer:
Mountains are cooler than plains because with increase in height the temperature decreases. EXPLANATION: Mountains are located in high elevations and plains are located in low elevations. Their respective heights are measured by term called as their height above sea level.
That the oxygen levels in the test tube increased and carbon dioxide levels decreased because plants produce oxygen using carbon dioxide
think its the second one,have a nice day