BER Check all the characteristics below that describe
elements
one type of atom
a pure substance
more than one type of atom
chemically combined elements
DONE

The two tubes contain bromothymol blue. after 24 hours, what will the color of the water be in tube b? a. green (it won't change) b. yellow c. blue d. colorless (clear)

Describe characteristics of a good respitory surface

Some substances but not other can cross the (blank) membrane of a cell