What would cause a person to have two copies of the bent thumb allele (tt)? 1. A person whose mother or father had two copies of the bent thumb allele will always have two copies of the allele.
2.A person with two copies of “t” inherited one from their mother and one from their father.
3. A person born with one “t” mutation is more likely to develop a second “t” mutation during their lifetime.
4. A person with two copies must have duplicated the “t” allele through mitosis early in development. (They inherited one, then doubled it)

Sally and sue were investigating the topic of friction in science. they used a small car and a ramp as seen in the picture to test what they were learning. they knew that they slipped easily on waxed floors but not on carpet, so they decided to change the material on the surface of the ramp to see what happened. they planned to use glass, carpet, aluminum foil, and sandpaper and run the car down the ramp over each surface. what would be the best research question to guide the girls' experiment? a) does the amount of surface area affect the friction on the moving car? b) will the car travel fastest on the glass surface? c) how does the angle of the ramp affect the speed of the car? d)do rougher surfaces tend to create more friction than smooth surfaces?