Models are simplified representations of of different complex systems. They also help to study very small or large objects.
Option B, D and E.
Explanation:
Models are very simplified representations of complex systems and organs or structures which are prepared to study those systems by scientists and normal people easily. Many structures of human body like cells or some tissues are very small in structure or microscopic in nature. So studying them are very hard without specific instruments which are not always available. Thus models are made to easily study those structures by scientists and even normal people and students.
B, the others are not testable under lab conditions.
Answer: A. Accumulate keratohyalin granules. B. Cells increase in size, some retain ability to divide. C. Cell membrane thickens. Cells imbedded in lipid matrix. D. Cells within this layer proliferate.
Explanation:
Answer: B. Any cells of the human body or placenta.
Explanation:
All types of cells in the human body can develop from pluripotent stem cells. Embryonic stem cells are also considered pluripotent.