PLEASE HELP ME ASAP Describe how each of these measurements of time provide a reliable reference to measure time.
1. Days:
2. Years:
3. Tree Rings:
4. Layers of Garbage:
5. Radioactive Dating:
6. Molecular Clocks:

i think the answer is b.

the three components of a nucleotide are the nitrogenous base, the phosphate group and the five-carbon sugar.

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

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.