Astudent explains the formation of the planetary system as follows.
"the birth of the planetary system begins with a rotating cloud called nebula which contains hot gases. when these gases cool, the nebula expands and becomes a flattened disk. gravitational force causes rings of gases to be left behind when the nebula expands. at the center of the nebula, the gases combine to form the sun and the planets form in the outer flattened portion of the disk.
what is the flaw in the students explanation?
a. the nebula contracts and shrinks instead of expanding
b. the gases in the nebula get heat

Asea turtle has washed up on a remote section of a beach. this known as a stranding occurs when a dead, sick or injured sea turtle washed up on the shoreline. which statment best explain why stranding should be reported immediately to local authorities

Use this dichotomous key for insect identification to identify the insect shown. 1. a. insect has one pair of wings. order diptera b. insect has two pairs of wings. go to #2 2. a. front wings thicker in texture than hind wings go to #3. b. front and hind wings are same texture throughout. go to #4 3. a. front wings are short order dermaptera b. front wings cover entire abdomen order coleoptera 4. a. wings with scale on all parts of their area. order lepidoptera b. wings without scales go to #5. 5. a. hind wings smaller than front wings. order ephemeroptera b. front and hind wings nearly equal in size. order odonata the insect pictured is in the order diptera. ephemeroptera. coleoptera. odonata.

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.