2. Who was Barbara McClintock? What was her study organism? What are transposable elements? What are
retrotransposons (these are the most common in your genome). What do the enzymes transposase and reverse
transcriptase do? What are some ways that transposable elements can cause microevolution?

the law of original horizontality explains:   why rocks appear in layers. correct answer: b the law suggests that all rock layers are originally laid down (deposited) horizontally and can later be deformed.   the principle is used by geologists to make assumptions about the relative ages of sedimentary rocks.

the statements that apply here about binary star system are

"have stars that might appear to wobble"

"often have one star that is brighter than other"

a binary star is a star system consisting of two stars revolving around their common barycenter. systems of two or more stars are called multiple star systems.