Which of the following represents an ecological niche? Honeybees making honey from flower nectar in a grassland ecosystem
The mud in a pond ecosystem
The cacti in a desert ecosystem
Robins and sparrows living together in the same tree in a forest ecosystem

the answer is b.) hydrogen bonds between bases.

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