A constant in an experiment is <u>B. </u><span><u>the quantity that must remain the same</u>. If it is constant, it doesn't change, so it cannot be variable. D makes no sense.
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Answer:
The form of cell to cell signalling that is been used is ENDOCRINE.
Explanation:
There are four ways by which cell signalling occur in the body, these are: endocrine, paracrine, autocrine and direct signalling.
Endocrine signalling is the biochemical process by which hormone secreting glands release hormones into the blood streams and that hormone has effects on target organs that are located far away from it. Endocrine hormones are usually stable and their effects usually last for long time.
Answer:
B) snow
due to the below freezing temperatures of the upper atmosphere then the slightly above freezing temperatures of the surface it would cause it to the rain to turn into snow
