A geologist studies a layered rock to determine its age. Bacterial fossils from Precambrian time are found in the rock’s upper layers, but no bacterial fossils are found in the rock’s bottom layers. Which of these conclusions about the fossils within the rock is best supported by the evidence?

A. The age of the entire rock is determined by the age of the bacterial fossils within it.
B. Most Precambrian organisms were too small to leave fossil remains so the age of the rock cannot be determined by examining this evidence.
C. Because bacterial fossils are found only in the upper layers, scientists can conclude that these bacteria evolved towards the end of Precambrian time.
D. The bacterial fossils must have been formed during a different time period because most of the rocks from the Precambrian have been destroyed due to tectonic activity.

15. one purpose of the tread pattern on a tire is to a reduce tire wear. b. reduce traction c. allow water to flow away from the tire. d. look impressive.

Dao makes a table to identify the variables used in the equations for centripetal acceleration. what quantities belong in cells x and y?

People with normal vision cannot focus their eyes underwater if they aren't wearing a face mask or goggles and there is water in contact with their eyes. in a simplified model of the human eye, the aqueous and vitreous humors and the lens all have a refractive index of 1.40, and all the refraction occurs at the cornea, whose vertex is 2.60 cm from the retina.with the simplified model of the eye, what corrective lens (specified by focal length as measured in air) would be needed to enable a person underwater to focus an infinitely distant object? (be careful-the focal length of a lens underwater is not the same as in air! assume that the corrective lens has a refractive index of 1.62 and that the lens is used in eyeglasses, not goggles, so there is water on both sides of the lens. assume that the eyeglasses are 2.05cm in front of the eye.)