Answer:
d. generals similarities in appearance
Explanation:
Classification in biology is the science of identifying, naming and grouping organisms into different categories.
Organisms were earlier grouped based on superficial attributes such as body similarity, habitat, etc. This system of classification is referred to as traditional or artificial system of classification.
Natural system of classification classify organisms based on mode of nutrition, complexity of body, complexity of cell, evolutionary relationships, etc.
The correct option is d.
