下表是1975～2001年各大洲各自然灾害次数占全球灾害总次数的比重(%)统计表。分析完成：①大洲自然灾害比重较低，主要的原因是(   )

    Hi, good morning. My name is Wang Xu and I'm1student of No.8 Middle School. This is our2.It's new and big.3the library, you can4books everywhere, but it is still very5.We Call read books and do our homework(家庭作业)there.6the desks and chairs? They are on the second (第二) floor of the library. Look! That7is Linda. She is a friend of 8 .She likes reading and she is a good student. I think she is like my 9 because she often10me study English.

（Ⅰ）设h（x）=f（x）﹣g（x），求h（x）的单调区间；

（Ⅱ）若存在x₀，使x₀∈ $\frac{a+b}{4}$ ， $\frac{3a+b}{5}$ 且f（x₀）≤g（x₀）成立，求 $\frac{b}{a}$ 的取值范围．

设奇函数f（x）的定义域为R，最小正周期T=3，若$f\left(1\right)\ge 1,f\left(2\right)=\frac{2a-3}{a+1}$，则a的取值范围是（　　）