Medical procedures once thought unethical, such as heart transplants or test-tube babies, are
now relatively common. Debate the ethical implications of human cloning for medical
purposes.

phylogenetic tree is the tree of life or evolution tree. it shows the different branches of evolution. the sequence goes like tissues - coelom - backbone - endoskeleton - segmentation

it cools slower in the earth meaning the crystals have more time to form than lava on the surface

there are so many examples for that in different areas, like biology experiment carried out in our lab recently.

here's one link:

the principles and empirical processes of discovery and demonstration considered characteristic of or necessary for scientific investigation, generally involving the observation of phenomena, the formulation of a hypothesis concerning the phenomena, experimentation to test the hypothesis, and development of a conclusion that confirms, rejects, or modifies the hypothesis.