A chromosomal mutation is best described as A. mutations that involve changes in the number or structure of chromosomes in a cell or organism
B. changes in the "reading sections of a protein code frame that affect the subsequent amino acids
C. an amino acid substitution that changes all of the subsequent protein codes on the chromosome
D. a change in the genetic make-up of an organism that causes speciation to occur in a population​

the most logical answer would be a

blue stars have the highest surface temp

stellar distances are usually expressed in light-years

the measure of a star's brightness is called magnitude

hope this !

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.