They would know if they see anything like traces of water or anything else that would be nessecary for a living organism to have. They look for these with technology like the hubble telescope as well as the drone on Mars to gather as much information as possible.
polar ice and grass land because
C, the first two don't make sense and the last one would support the opposing view point.
Tetraploidy will occur.
<h3><u>Explanation</u>:</h3>
The process of sexual reproduction is very necessary to maintain the genetic setup of the species over the races.
The normal chromosome content of a cell is called diploid state of cell. Its represented by the expression 2n. The cell division that takes place before the gamete formation is called meiosis. This cell division makes the chromosome number of the cells halved. So haploid cells are produced. Its represented by n.
Now as the gametes fuse, both the n becomes 2n and diploid state is regained.
But if the meiosis don't occur in the gametes, the gametes will remain 2n. So after fertilization, it becomes 4n. This state is called tetraploidy.