Why is the percentage of food eaten a good number to use explain

A percentage compares the number of birds in the flock to the total number of birds in all flocks.

If the percentage is high, the flock is more successful, so the flock should grow.

If the percentage is low, the flock is struggling to eat, so the flock should shrink

during the process of dna replication, brdu can replace thymidine and incorporate into the newly synthesized dna, cell proliferation thus can be reflected in the extent of brdu incorporation.