问题
Why do scientists think deltas near the lake may hold secrets about past life on Mars？ 查看材料
A: Because similar places on Earth have become natural deposits of markers of life.
B: Because someone has put secrets about past life on Mars there.
C: Because past life has been found in other deltas on Mars.
D: Because some people are said to have already seen life marks there.
B: Because someone has put secrets about past life on Mars there.
C: Because past life has been found in other deltas on Mars.
D: Because some people are said to have already seen life marks there.
正确答案是：
