Protoplanets are bodies or celestial objects which have the same size as the moon or a bit bigger. These bodies develop to eventually become planets. Therefore, the answer to this item is most likely letter D. outer planets.
One problem with this hypothesis is that the student didn't write about why this hypothesis might work - what is the underlying mechanism. The thing is that one might want to write the underlying mechanism or explanation in his hypothesis. Another problem with this hypothesis is that it's very hard to measure and be sure that following exposure to white chocolate, people are happier and that it's not a consequence of something else.
The history of life on Earth began about 3.8 billion years agohumans have been around for a mere 0.004% of the Earth's history
The answer for the given question above about a cladogram showing the evolutionary relationships between different vertebrates is option A. <span> Amphibians and birds share a more recent common evolutionary ancestor than sharks and birds. I hope this helps.</span>