] Circle the letter of each sentence that is true about water's structure.
a. Water is made up of atoms bonded to form molecules.
b. Water contains half as many hydrogen atoms as oxygen atoms.
c. Water molecules tend to push away from each other.
d. The chemical formula for water is H20.

Which of the following is a macronutrient? carbohydrates lipids amino acids all of the above

_tissues respond quickly to outside stimuli a) epithelia b)nervous c)muscular d)muscular and nervous

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas