I do not think that testing should be done on animals. Why are you testing human products on animals in the first place? Test products that you want to use on the people that will it be given to.
Answer:
Penia, eardrum, and ear canal
Explanation:
In his theory of Cognitive development, Jean Piaget proposed that humans progress through four developmental stages: the sensorimotor, preoperational, concrete operational and formal operational period.
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