Most lightning takes place within a cloud when the charge se

Most lightning takes place within a cloud when the charge separation within the cloud collapses.However,as the storm cloud develops,the ground beneath the cloud becomes positively charged and lightning can take place in the form of an electrical discharge between the negative charge of the cloud and the positively charged ground.so even though it represents only 20 percent of all lightning,it has received a lot of scientific attention.题目问作者为什么提到【Lightning that strikes the ground is the most likely to be destructive】,我选的选项是：explain why scientific of this form of lightning is very important 正确答案是：explain why this form of lightning has been investigated so much我想请问一下这俩有啥区别么?为什么不是我那个答案?