21 , The most valid and reliable test of the hypothesis , more pine seeds germinate after a forest fire , would include an experimental group of pine seeds that was recovered from a fire area and pine seeds that were —
22 . Which of the following might be referred to as " working macromolecules "?
23 . Lipids are used for
24 . The first step of the scientific method involves :
25 . Identify two specific polysaccharides and describe where they are found and what their biological role is .
26 .
Enzymes will usually react with only one substance . This can be explained by the ' lock and key ' theory . If this theory is correct , which of the following substances , represented by P , Q , R and S would be acted on by enzyme A ?
Which particles have approximately the same size and mass as each other ?
A solution with a pH below 7 is
What is a solution that has an excess of H + ( hydrogen ) ions ?
The group of biologically important organic compounds responsible for storage and transfer of information is
feedback acts to maintain a homeostasis feedback loop and reverses the direction of change .