What was the major contributor of oxygen to earth's early atmosphere ? A) photosynthesis

B) Organic respiration

C) ozone decomposition

D. Decomposition of ocean water

Explain your answer in your own words

a researcher conducts an experiment on the secretion of a particular hormone in mice. scientists inject mice with a substance that stimulates the production of the hormone. the scientists then test the levels of hormones produced by the mice. the tool used to measure the hormones consistently detects the levels at 10 points lower than the actual hormone levels in the mice. this tool makes measurements, but the measurements aren't .

explanation:

no u