The model that assumes that evolution proceeds with a slow successive change in a given evolutionary line are referred to
a. the sympatric model.
b. the allopatric model.
c. successive descent model.
d. gradualism.
e. punctuated equilibrium

The correct answer is - d.  gradualism.

Explanation:

Gradualism is a model of evolution that explains that the smaller variation in an individual organism that is occurring over a period of the time is to the betterment of the organism in their environment.

These changes or variations allow them to thrive and survive with a slow successive change in an evolutionary line or the whole population. It is a consistent process.

Thus, the correct answer is - D. gradualism.

a

explanation:

an organism's phenotype is the  form of a trait  that it  displays. for  flowercolor, a pea  plant  can  display  a phenotype of purple or white flowers. an organism's  genotype  is the alleles of a gene it contains. based on his data, mendel concluded that a phenotype can be  determined  by more than one  genotype.