I think the correct answer would be D. When solving a problem, it is important that you first know the root cause of a problem. So, you ask yourself why such a problem happens to you. From that, you can trace back everything that happened and determine what is the cause.
Answer: C
Explanation: It is correct
Answer:
green house effect mean the ozone slightly decreased and make radiation pass
Explanation:
their's no advantage and it affect people couse cancer
Explanation:
i think aliens do exsist
different birds have different to winter like some hibernate and some migrate