Unit 1: Chemistry of Life

Biology is the

• study of components that make up organisms.

• study of life.

• categorization of organisms into similar groups.

• study of how organisms give rise to offspring.

One mechanism of evolution, or change over time, is

• biotic.

• systems interactions.

• natural selection.

• DNA.

Many organisms use sugars as a source of energy to power the cell. This observation suggest that the pathways that break down sugars

• arose relatively recently.

• arose early in life's history.

• are different in different species.

• sugars are not necessary for life.

A hypothesis is

• the cause of a scientific phenomenon.

• the solution to a scientific problem.

• a hunch or guess.

• a tentative explanation of how nature functions.

An independent variable is

• the factor that differs in the test group compared to the control group.

• the order in which one measures the data collected in an experiment.

• a factor that is larger or smaller than other factors in an experiment.

• the result of the experiment that is being observed or measured.

You decide to test whether helium is light enough to cause balloons to rise. In the first group, you fill the balloons with helium. In the second group, you fill the balloons with air. What is the dependent variable in your experiment?

• the presence or absence of helium

• the group of balloons that receives the helium

• the group of balloons that receives the air

• whether the balloon rises or not

A hypotheses is

• supported when data contradict it.

• proven when data can support it.

• modified when data contradict it.

• rejected when data support it.

The element sodium (Na) has an atomic number of 11 and an atomic mass of 23. Calculate the number of protons and neutrons in Na.

• 11 protons and 11 neutrons

• 11 protons and 10 neutrons

• 11 protons and 12 neutrons

• 10 protons and 13 neutrons

Which type of bond is formed between a sodium ion and a chloride ion?

• ionic

• neutral

• polar covalent bond

• nonpolar covalent bond

Which type of bond is formed between two oxygen atoms?

• ionic

• neutral

• polar covalent bond

• nonpolar covalent bond