naturally occurring iron , fe, contains 4 isotopes: 5.82% (53.94 amu), 91.66% (55.935 amu), 2.19% (56.935 amu), and 0.33% (57.933 amu). calculate the average atomic mass of iron.

Afish fossil is found in a rock. a foot bone and tooth are found in an older layer of the same rock. what can scientists learn from the rock? a) the area changed from land to water. b) the area changed from water to land. c) the area has always been land. d) the area was once an ocean.

Layer r contains a well-known index fossil that is 100 million years old. based on this information and the principle of superposition, a. layers t and m are older than 100 million years, and layers x and g are younger than 100 million years. b. layers t, m, x, and g are all older than 100 million years. c. layers t and m are younger than 100 million years, and layers x and g are older than 100 million years.

Which of the following is a difference between a prepaid tution plan and a college savings plan