Answer:
A.The hole in the ozone layer
Explanation:
• Montreal protocol is an international treaty that was signed to control the use of substances that are resulting in the depletion of the ozone hole.
This treaty was signed in the year 1987 and became effective form 1989.
• Since the time that this treaty has come into force, there has been a significant improvement in the ozone hole that was observed over Antarctic as it's size has decreased.
• This improvement has been possible because the treaty helped to phase out chemicals such as chlorofluorocarbons, carbon tetrachloride, etc. that are responsible for ozone hole depletion.
Natural selection occurs to give help the best survival chance to the organisms.
Answer: Mitochondria and chloroplasts.
Explanation: Mitochondria create energy for both plant cells and animal cells through cellular respiration. Chloroplasts create energy for plant cells through photosynthesis.
These dark areas are called maria. They are thought to be formed by volcanic eruptions in the moon's history.hope this helped:)
