2. which of the following can be thought of as opposites? (3 points)

a) white dwarf and brown dwarf

b) black hole and protostar

c) neutron star and pulsar

d) red giant and blue giant

3. which statement is true concerning the evidence for black holes? (3 points)

a) scientists can see black holes with powerful telescopes.

b) scientists can see the effect of black holes on nearby stars.

c) scientists can see trails left in space by black holes.

d) there is no evidence for black holes.

Two students are working together on an experiment that measures the effect of different liquid fertilizers on the thickness of plants’ stems. which is most likely to result in the greatest amount of error in their scientific experiment? a.one student measures the plant stem widths by using calipers. the other student measures the widths of the same plant stems again by using a different pair of calipers. b.one student measures the plant stem widths by using calipers. the other student types the measurements as they are taken into a computer spreadsheet. c.one student weighs liquids for the experiment by using a calibrated scale. the other student weighs liquids for the experiment by using a different calibrated scale.