We still have a trace of the reptillian yolk sac, of course, but it's vestigal. And it's all one way. There's no creation theory that could possibly account for these facts. Inferences may be drawn from various sources, such as consensus or from direct examination of the evidence. Consensus may suggest that species evolve from other species while the evidence may suggest otherwise.
Inference is simply a logical extrapolation of the evidence.
For example, the electron. This is simply an inference that is the logical conclusion of a series of experiments. Evolution is just such an inference. This seems to be the prevailing view of evolutionists. It avoids direct confrontation of the evidence, declares the opposition uneducated, and finds solace in name calling.