Maria and Soledad were digging in the backyard. They found pieces of flat rock deep in the hole they had dug. Some of the rocks had imprints of fish, like one you see here. They showed the rocks to their parents. "What do think this back yard once looked like? " asked their father?
The backyard used to be a river or lake. After the river/lake dried up, a fish got pressed against the rock, eventually making a fish pattern.
Answer: The backyard was once underwater, maybe the bottom of a lake.
Explanation: