Answer:
A. Quaternary
Explanation:
We came around Quaternary time frame. This period is called the "Age of Humans"
Studies of the similarity of the DNA in wasps and bees suggest that the first bees appeared about 130 million years ago, 50 million years before the first known fossil bee, and probably very shortly after the first flowers evolved in the Cretaceous.
Answer:
Muscles move body parts by contracting and then relaxing. Muscles can pull bones, but they can't push them back to the original position. So they work in pairs of flexors and extensors. The flexor contracts to bend a limb at a joint.
Explanation:
First you need to add all the fractions you know. 3/12 + 1/12 = 4/12. Then you subtract your answer of 4/12 to 1/2. But you first need a common denominator. A common factor is 12 for example. 4/12 stays the same, but 1/2 becomes 6/12. 6/12, or 1/2 minus 4/12 is 2/12. Your answer is 2/12 or B.