scientific understanding can always be challenged snd even changed, with new ways of observing and with different interpretations

True

Explanation:

Conclusions made from scientific research or understanding can always be challenged by anyone with new ways of observing and with different interpretations. This is the essence of the repeatability or reproducibility of scientific experiments.

Scientific research must be reproducible and if the earlier conclusions or understanding is found to be somehow inadequate with overwhelming evidence, they are modified or even changed completely in order to accommodate new facts.

Hence, the emergence of new ways of observing different interpretations can lead to new/different conclusions from the same research. If the new conclusions gain enough evidence, it becomes the new theory.

eukarya because is is like alche and b is bacteria and d is animals

explanation:

oxygen = 21% of the atmosphere

nitrogen = 78%

carbon dioxide = 0.1%

argon =0.934%