The Exploratory Life-Sciences Experiments Aboard the Viking Spacecraft Landers Found

question 268

Multiple Choice

The exploratory life-sciences experiments aboard the Viking spacecraft landers found evidence of:

• A) a very sterile environment in which life could not have existed and a very chemically inert soil, reacting with almost no reageants.
• B) primitive life-forms such as elementary bacteria that should not be a hazard when humans explore Mars.
• C) very reactive chemistry in the Martian surface rocks, but no evidence of life or remnants of life-forms.
• D) primitive life-forms that had existed on Mars earlier in its history but had not survived.

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Definitions:

Primary Succession

is the process of ecosystem development or recovery on a site where no biological community previously existed, such as on bare rock or lava flows.

Facilitation

The process by which certain living organisms make an environment more suitable for other organisms to inhabit, often leading to changes in the community composition.

Ecosystem

A biological community of interacting organisms and their physical environment, functioning as a system through nutrient cycles and energy flows.

Immature Ecosystems

Ecosystems in the early stages of development, which have yet to reach a stable climax community and are characterized by rapid changes in species composition and structure.