Hope this helps so 31 animals are walking towards the river right? ok so
1 rabbit + 6 elephants then If every elephant seen 2 monkeys then 6*2 is 12.
= 19 animals.
Then another 12 animals if there is a parrot for every monkey.
19+12 is 31
so your awnser is 31
Answer: I'm not going to write your whole essay for you, but some good reasons to use would be: A change in atmosphere, they can experience what life is like on a different planet, they can get a chance to learn more about mars or anything else about space, and they can compare and contrast how different mars is from earth along with make new memories on a different planet.