Immediately above the sun's photosphere is the blank which is the sun's lower atmosphere

Explain how paleontologists use trilobite fossils as index fossils for various geologic time periods.

Dna, in the nucleus carries the genetic code for making proteins in ribosomes. in the diagram, b, represents the proteins produced. dna cannot leave the nucleus to carry the genetic information to the ribosome where proteins are produced. how does the genetic code get from the nucleus to the ribosome? what does a represent? now

The diagram shows a chicken embryo and a human embryo