There are approx 100 billion
Answer:
The correct answer would be C. The tortoises provided evidence that different species have adaptations suited to their particular environments.
Darwin observed that how different environment on different island lead to the development of different species as a result of adaptations and natural selection.
For example, tortoise inhabiting well-watered islands which used to have short and cropped vegetation had developed a dome-shaped shell.
In contrast, the tortoise inhabiting the arid islands had developed saddle-shaped shells. It is because they needed to stretch their necks in order to reach branches of cactus and other vegetation available in the area.
Consequently, they developed long necks and high peak to the front edges of their shells. It made it possible for them to stretch their heads vertically.
The correct answer is B - homozygous
