The world’s population is getting larger and larger so scientists are trying to new ways

问题补充：

The world’s population is getting larger and larger, so scientists are trying to new ways to solve the food shortage.

A. keep up with

B. come up with

C. make up with

D. catch up with

答案：

A. keep up with

(答案→)B. come up with

C. make up with

D. catch up with

解析：keep up with赶得上，和……保持联系；come up with提出，想出；make up with与……重修旧好；catch up with赶上，追上。句意：世界的人口数目正在变得越来越大，因此科学家们正在努力想新办法来解决食物短缺问题。结合语境可知选B。