据说万能的人大经济论坛能解答所有问题，那么我来请教：

CFA 1级的economics的内容。

为什么不可再生（non-renewable）资源的供给曲线是水平的（perfectly elastic），而可再生（renewable）资源的供给曲线是垂直(perfectly inelastic)的呢？（前提，Q是纵轴，P是横轴）我怎么觉得应该是反过来呢？头想大了也没给想出来==

如果哪位大牛明白，一定要告诉我啊!!!

PS, 附一个书上的解释如下: assuming a competitive market for water (renewable) ,the price will be determined by demand. the supply of renewable resources at a point in time, or per time period, is fixed.......therefore, the supply of a renewable resource is, therefore, independent of  price and is perfectly indelastic.
the quantity of a non-renewable resource that has already been discovered is called the known stock of the resource. Though the known stock is fixed at any point in time, it tends to increase over time as technological advances make more resources accessible. Thus it is perfectly elastic at a price that equals the present value of the expected next-period price.