Giving 10 pts today to help with earth space science?

[sports4me]

1) Certain groups of fossils, which are commonly found in sedimentary rock, have been radiometrically dated and have been found to be a certain range of ages old regardless of where on earth they are found. Geologists have come to use these fossils as a marker for the relative age of the layer the fossils are found in. These types of fossils are called
A. trace fossils
B. marker fossils
C. index fossils
D. faunal fossils
We have a radioactive isotope - RI-1. It decays and forms daughter element 1-DE-1. The half-life of RI-1 is 12 my (million years). A geologist has used radiometric dating to determine that the rock being dated has an approximate age of 36 my. How many half lives
A. 1
B. 2
C. 3 (i think it is this one)
D. 4
When we measure time we can measure absolute time or relative time. When we measure in relative time we use the known age of one object to give an age to another object.
True or False(I think it is False)
Plz don't guess this is a study guild 4 test