<span>D. Overcrowding and destruction of rain forests</span>
Answer:
If we do nothing, the world will become significantly less habitable. ... Scientists have studied global warming for more than 100 years. ... The cumulative effect is to raise the planet's temperature. ... Scientists have taken detailed measurements of carbon dioxide (CO2) levels since the late 1950s
Explanation:
Answer: The Earth is a closed system for matter
That is a list of all basic elemental materials on our planet. Because of gravity, matter (comprising all solids, liquids and gases) does not leave the system.
-4x^2-4xy+6y^2 hope this helps
