The answer here is D, and it's kind of obvious. But you probably already knew the answer and are just doing this for piece of mind.
Explanation: Just the fact that we don't know whether or not there even is extraterrestrial life rules out every other answer, without even needing to go in depth.
(Okay, I read your question completely wrong, it's asking for which one of these has been solved isn't it?)
This is tough because all of these other than D have been figured out. Go with the methane atmosphere then.
Answer:
its D
Explanation:
Its D cause plants use their roots to get water and the vascualar tissues are found in the root most of the time.
Answer:
rice cultivation.
Explanation:
There are two methods of sowing a crop in the field i. e. sowing of seed and transplanting. Seeds sowing in the field is used for almost all the crops except rice in which transplantation is done. In transplanting method, plants are grown inside a nursery and when the plant reaches to a certain height, it is transported to the field. This method is done in the cultivation of paddy rice because water is present at a certain height in the field and rice is the only crop in which roots respire in water.
