Why is DNA a useful evolutionary clock?
DNA mutations cause organisms to diverge evolutionarily from one
DNA is the only substance in an organism that never changes.
DNA contains no carbon, so it is not affected by radioactive decay.
DNA decays steadily over time once an organism dies.

The graph shows the solubility of several different salts in water, across a range of temperatures. according to the graph, which salt can dissolve at a concentration of about 60 g/100 cm3 of water at 40 degrees celsius?

What happened to rosalind franklin in 1956?

Which is an advantage of having memory cells when a pathogen is encountered for a second time. a) the memory cells are what proliferate into clones of cells in response to the binding of an antigen. b) memory cells are vital to the primary immune response in that they immediately recognize pathogens even at the first encounter. c) memory cells are essentially effector cells that are short lived and attack antigens even without having a receptor specific to that antigen. d) it ensures that more lymphocytes with a receptor specific to a particular antigen will be present than in a host that had never encountered that pathogen.