The techniques used to study molecular evolution are based on the comparison of nucleotide and amino acid sequences among species.
a) true
b) false

True

Explanation:

In molecular evolution, the similarity in genome of two or more different organisms is studied. These changes are observed at DNA and protein level to study the variations/evolutionary changes brought in by the long term mutation. Nucleotide sequences of the DNA are assessed to determine the changes, its effect, cause and rate of occurrence. All the structural configurations of protein ranging from primary sequence to three dimensional structures are studied  

Hence, the given statement is true

what statement best describes the difference between the sympathetic and parasympathetic nervous systems?

the sympathetic nervous system prepares the body for intense physical activity and is often referred to as the fight-or-flight response. the parasympathetic nervous system has almost the exact opposite effect and relaxes the body and inhibits or slows many high energy functions.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.