<span>A tiger looks so much different as an adult than it did as a single fertilized egg because it developed through different stages from being a zygote (fertilized egg), to becoming an embryo (where it experiences intense cellular changes), to becoming a fetus (where it gains a great measure of cell specialization, and develops distinct tissues and organ systems). After birth, the tiger still undergoes further growth and development into adulthood. This is largely regulated by the expression of different genes at different times and also by environmental factors.</span>
What are the answer choices?
Answer:
Cells are considered the basic units of life in part because they come in discrete and easily recognizable packages. That's because all cells are surrounded by a structure called the cell membrane — which, much like the walls of a house, serves as a clear boundary between the cell's internal and external environments.
Can you explain a little more about the question please?
I believe your answer is B... I hope this helps!