A type of trilobite is used as an index fossil. These fossils were made around 540 million years ago. A scientist finds a trilobite fossil within layer 3 in the diagram (picture).

What can the scientist conclude from this finding?

A. Fossils from layer 9 are the newest in the diagram.

B. All the fossils in this diagram are at least 540 million years old.

C. Layer 1 has the newest fossils in the diagram.

D. Fossils in layer 5 are less than 540 million years old.

Which of the following explains why a tree is often used as a model to represent the principle of common descent

Which of these is not an example of molecular homology? 1. use of dna and rna as genetic material 2.use of glycolysis as the first step in cellular respiration in both plants and animals 3. the lack of an igf-1 gene in prokaryotes 4. the use of aldolase b to break down fructose in bacteria, plants and animals

When does a spring tide occur? question 9 options: they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur twice a year in the spring and fall. they occur on the date of the vernal equinox each year, no matter what stage the moon is in. this is why they are called spring tides. they occur when the sun, moon, and earth are at 45-degree angles from each other. this happens once every spring. they occur when the sun, moon, and earth are aligned. in spite of their name, these tides occur all year long.