To reduce the risk of drowning. You are prone to drowning without the assistance of a floatation device.
Troposphere -----------------
Answer:
C. mRNA serves as the template for DNA, which carries the code to the ribosome for protein construction.
For every million parsecs of distance from the observer, the rate of expansion increases by about 67 kilometers per second. The Hubble parameter is not thought to be constant through time. There are dynamical forces acting on the particles in the universe which affect the expansion rate.