Commensalism is a symbiotic relationship where . A. both species benefit

B. one species benefits and one is unaffected

C. one species benefits and the other is harmed

The diagram illustrates the activity of vesicles during a cellular process.

Which statement about dna replication is true? a. eukaryotes only have one circular chromosome that unwinds at multiple locations. b. eukaryotes can only replicate one segment of a chromosome at a time. c. prokaryotes can only replicate their single circular chromosome in the nucleus. d. prokaryotes only have one origin of replication to initiate replication.

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