HELP THSI IS 100 POINTS A group of students is doing an experiment where they roll a ball down a
ramp and then measure how far across the floor it rolls. The factors that are
the same each time are: - the ball - the ramp, including its length and angle
to the surface - where on the ramp the ball starts from The students do
change the type of surface the ball rolls on. What is the independent
variable in this experiment? *
ramp
ball
distance
type of surface the ball rolls on. What is the independent variable in this experiment

The Ramp.

Explanation:

You don't move the ramp, the ramp isn't dependent on the ball or the distance.

The distance depends on the ball and ramp

the ball depends on the ramp

relative dating involves things like higher layers are most recent than rocks lower in the sequence. this can be extended to the known sequence of fossils. rocks containing rabbit fossils are later than those containing dinosaur fossils.  

absolute dating methods mainly use radioactive elements that have known rates of decay and produce recognizable products. for example potassium 40 decays to produce argon. once a rock has solidified the argon is trapped. by measuring the argon and potassium0 you can get an accurate number for the age.  

some other methods are good for archaeological ages. dendrochronology involves recognizing the sequence of tree rings. the orientation of magnetized particles in baked clay can be used to date a fire.

hope this .. .

i think a) betsy can donate only blood to mark is correct because, mark and betsy have the same blood type. whereas nobody else has b+ blood so betsy can't donate to them.