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.
Answer:
B, deoxyribose means it has fewer oxygen molecules than ribose, choice B has fewer oxygens.
Explanation:
Dna stands for deoxyribose
The answer is hydrogen bond.
Between water molecules, hydrogen bonds can be seen, which is due to the polar nature of water.
Also called simple sugars, they are the most basic units of carbohydrates
