About 25 of the 92 natural elements are known to be essential to life. Which 4 of these 25 elements make up approximately 96% of living organisms?

1. carbon, sodium, hydrogen, nitrogen
2. carbon, hydrogen, nitrogen, oxygen
3. oxygen, hydrogen, calcium, nitrogen
4. carbon, oxygen, phosphorus, hydrogen

B

Which of the following are qualities of any good scientific hypothesis?

1. It is testable
2. It is falsifiable
3. It produces quantitative data
4. It produces results that can be replicated

I and II

Plants convert ____

1. sunlight to chemical energy
2. chemical energy to mechanical energy
3. sunlight to mechanical energy
4. mechanical energy to chemical energy

A

If an atom has a charge of +1, which of the following must be true?

1. It has the same number of protons as electrons
2. It has one more electron than it does protons
3. It has one more proton than it does electrons
4. It has two more protons than neutrons

C

Atoms have no electric charge because they have ______

1. an equal number of protons and electrons
2. an equal number of charged and uncharged subatomic particles
3. uncharged neutrons in their nuclei
4. an equal number of protons and neurons

A

A localized group of organisms that belong to the same species is called a ____

1. family
2. ecosystem
3. population
4. community

C

What makes lipids/fats hydrophobic?

1. the carboxyl group at one end of the molecule
2. presence of relatively nonpolar C-H bonds
3. the glycerol moiety
4. their long carbon skeleton

B

Which of the following categories includes all others in the list?

1. carbohydrate
2. polysaccharide
3. starch
4. disaccharide

A