In an ecosystem, all the trophic level in a food web are closely interlinked and any change in one level is bound to affect the other levels. The various trophic levels may correspond to producers (such as grass and plants), primary consumers (such as deer), secondary consumers (such as tigers or lions, etc.), etc. If we reduce the land available or necessary for sustaining the ecosystem by half (5 acres instead of 10 acres).
A forcible overthrow of a government or social order, in favor of a new system
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.
Combination of alleles for two genes that are located far apart on the same chromosomes. In this figure, label the column that shows meiosis and the column that shows mitosis.
The Oxidation-Fermentation Test is used to differentiate bacteria built on their capability to oxidize or ferment specific sugars.
Once microbes are inoculated,-One tube is sealed with a layer of sterile mineral oil to promote anaerobic growth and fermentation.-The other tube is left unsealed to allow aerobic growth and oxidation.
Organisms able to ferment the carbohydrate or ferment and oxidize the carbohydrate will turn the sealed and unsealed yellow throughout.
Organisms able only to oxidize the sugar will turn the unsealed yellow medium and leave the sealed medium green or blue.
Fragile fermenters will convert both tubes slightly yellow at the top.
Organisms not able to metabolize the sugar will either produce no color change or will turn the medium blue due to alkaline products from amino acids degradation.
Since Pair #1 showed complete yellowing for sealed and unsealed, these Organisms able to ferment the carbohydrate or ferment and oxidize the carbohydrate. So our interpretation will be that the organism has: Oxidation and fermentation OR fermentation only.
For tubes #2 and #3, the sealed tubes were green throughout suggests that they need oxygen for aerobic growth, and the fact that their unsealed tubes showed light yellowing is evidence for oxidation. Sealed - Green and Unseal - Yellow. Our interpretation for these pairs of tubes would be : Oxidation
Tube 1 can be either Oxidation and fermentation OR fermentation only. So reliability of this needs to be confirmed more with additional testing.
Tubes 2 and 3 are most reliable because they can only be oxidation only and no fermentation.