Which of the following types of molecules help to hold the DNA strands apart while they are being replicated? a
primase
b
helicase
c
ligase
d
single-stranded binding proteins

Which of the following is not a symptom of desertification? a) decrease in salt content of the soil b) lowering of the water table c) reduced surface water d) increased soil erosion e) loss of native vegetation

How do you date a sample of rock that you suspect as being one of the earliest on earth

Nephrons, the functional unit of kidneys, are responsible for formation of urine. the sentences describe situations that are the result of problems in the urine formation process. for the nephron shown below, match each situation to the step in the urine formation process where the problem lies.