What is often a problem when calibrating a molecular clock? A. There are frequently not enough negative mutations to accurately calibrate the clocks.
B. There are many different clocks, each of which "ticks" at a different rate.
C. The clocks use mutations that are difficult to identify and track.
D. The frequency of crossing over is used to calibrate the clocks.​

Cold case files recently began re-investigating an old murder case. the murder took place in the park; a young man, james, was hit over the head with a brick and killed. police suspected the jealous former boyfriend of james' wife, karen. whoever killed james may have washed their hands in a near-by bird bath as detectives found blood in the bird bath. since the murder took place before dna fingerprinting was available, the suspected killer, ronnie, went free. detectives are now reviewing the blood evidence using dna fingerprinting. based on the dna fingerprints of all possible suspects, who is james' killer?

The body of water found at number 4 on the map above is the

Which statement best compares aerobic and anaerobic respiration