coach- review ch 1

a student carries out an investigation on a strain of bacteria that is used to decompose oil spills. she places equal numbers of the bacteria in 3 different salt solutions: 2.5%, 3.5%, and 4.5%.she keeps all the solutions in a lighted incubator at a temperature of 22 C. after 3 days, she removes the samples and counts the number of bacteria in each. which question is the student investigating?

• do oil-decomposing bacteria grow well in a warm, lighted environment?

• are the bacteria being studied the best strain to use in clearing oil spills in ocean water?

• do bacteria in a saltwater solution grow best at 22 C?

• does salt concentration affect the growth of this strain of bacteria?

a biology student is carrying out a scientific experiment with the setup shown below. the student is conducting a test to determine the affect of pH on the germination of seeds. what error in the experimental setup will make the results unreliable?

• the student is using seeds only from edible plants for the independent variable.

• the seeds are being grown in petri dishes without soil

• variables other than the independent variable are not being controlled

• the experiment contains too many trials to provide accurate data.

a researcher is investigating how the amount of carbon dioxide in the air affects the rate of photosynthesis in a certain type of plant. she uses 10 identical plants an dplaces them in 10 closed environments that are identical except for the amount of carbon dioxide in the air. she measures the amount of oxygen each plant produces the determine their photosynthetic activity. which would be the best data display for comparing the photosynthesis activity of the plants?

• labeled sketch

• circle graph

• bar graph

• line graph

which piece of equipment enables scientists to examine living cells?

• telescope

• compound microscope

• transmission electron microscope (tem)

• scanning electron microscope (sem)

which is the main reason scientific journals are typically the most reliable sources of scientific information?

• they are written by scientists.

• they are peer reviewed

• they are edited by the government

• authors are heavily fined if info is incorrect

you are outside on a bright summer morning. you notice many yellow dandelion flowers growing in a lawn.nthat night, you noticed that the dandelions have closed up so the flowers are no longer visible. when you go outside the next day, you observe that the yellow flowers are visible again. which is a likely reference that would explain your observations?

• dandelion flowers open in response to light

• dandelions die when the sun goes down

• dandelions live for one day then are replaced by new flowers

• sunlight has no effect on the time of day when dandelions flower.

why are competing or alternative observations of scientific phenomena considered a strength of science?

• alternative explanations show that data cant be trusted

• alt. explanations provide a source of new, testable ideas that can result in new information.

• alt. explanations show that errors were made in research

• alt. explanations are never considered a strength of science

a student needs to calculate the density of an egg. which tool should she use to determine the mass of her sample?

• spring scale

• graduated cylinder

• triple-beam balance

• calculator

a student plants pea seeds in 3 identical pots. each pot contains 3 seeds.the first pot contains potting soil, the second contains clay, the third contains sand. the seeds are given the same amount of water and sunlight for three weeks. what is the independent variable in the experiment?

• # of seeds

• kind of soil in which the seeds are planted

• the amount of water and sunlight

• the height that the plants grow to