When the heated part of the mantle rises through the cooler part , this is an example of Convection.
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.
Answer:
While skeletal muscles are arranged in regular, parallel bundles, cardiac muscle connects at branching, irregular angles, called intercalated discs. Striated muscle contracts and relaxes in short, intense bursts, whereas smooth muscle sustains longer or even near-permanent contractions.
The answer is hard tissue.
Usually, hard tissue, such as bones and teeth or exoskeleton is much more preserved than soft tissue (organs, skin, etc.). Fossils become fossils by a process of mineralization. Hard tissues are more mineralized during life than organs. So it is no surprise that hard tissues take part in the process of mineralization and is preserved in fossils, unlike soft tissues.