I would have to say cool air begins to sink and warm because precipitation is pretty much snow or rain
Answer:
<h2>Upper epidermis.</h2>
<em><u>H</u></em><em><u>o</u></em><em><u>p</u></em><em><u>e</u></em><em><u> </u></em><em><u>t</u></em><em><u>h</u></em><em><u>e</u></em><em><u> </u></em><em><u>a</u></em><em><u>n</u></em><em><u>s</u></em><em><u>w</u></em><em><u>e</u></em><em><u>r</u></em><em><u> </u></em><em><u>h</u></em><em><u>e</u></em><em><u>l</u></em><em><u>p</u></em><em><u>s</u></em><em><u> </u></em><em><u>u</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em><em><u>.</u></em>
C) The viewer's eye
I had biology last year and i passed it with a A+ and i know everything about microscopes and such.
Answer:

Cost : The expenditure incurred by a producer on the factor as well as non-factor inputs for a given amount of output of a commodity.
You need to elaborate more