Proteins may act as buffers because the free carboxyl group can release hydrogen ions.
a) the free carboxyl group can combine with hydrogen ions.
b) the free carboxyl group can act as a base.
c) the free amino group can release hydrogen ions.
d) the free amino group can act as an acid.

Ageologist determines that a sample of a mineral cant be scratched by a steel nail but can be scratched by a masonry drill bit based on this information the sample mineral has to be softer than

For the strategies below, decide whether they are best described as demand-side solutions or supply-side solutions to meeting human needs for fresh water. remember that a demand-side solution reduces demand for fresh water, whereas a supply-side solution increases the supply of fresh water. (a) damming a river to create a reservoir (b) desalinating seawater (c) a nation invading a neighboring country to access their rivers (d) raising water prices for consumers and businesses (e) providing tax breaks for companies that use less water (f) replacing inefficient irrigation with more-efficient drip irrigation to grow crops (g) requiring low-flow showerheads in all new homes

There are only about 250,000 known fossil species. true or false