(a)(i) Difference between genotype and phenotype: A person's genotype is the sum total of the person's genetic constitution; while the phenotype is the observed trait/physical characteristics.
(ii) Factors which determine genotype: -

Genotype of parents
Mutation.

Factors which determine phenotype: -

Genotype
Environment;
Diet
Health.

(b)

Phenotypic ratio 3 black 1 white puppies
(b) Calculation: The number of white puppies using the phenotypic ratio
3 black: 1 white = 24
Total No of puppies produced = 240 .
No of white puppies produced = ¼ x 240 = 60 white puppies
(b)(ii) Number of black puppies = ¾ x 240 = 180 black puppies
OR calculation b(ii)
No of black puppies ¾ x 240 = 180
b(i) No of white puppies ¼ x 240 = 60