I think the correct answer would be A. The yolk sac becomes the placenta. It is membranous sac that is attached to the embryo. It provides all the nutrition and the blood cells needed by the embryo. It is also called the umbilical vesicle.
Temperature, viscosity, and amount of dissolved gases
The answer is B) the science of heredity
In taxonomic, the organism is classified based on some similarities. In upper division, the similarities should be more general and in the lower division, the similarities will be more specific. It was mostly based on an organ, example: vertebrate.
An organism with the same phylum could be put in different order.
But the organism with the same order should have the same phylum and class too since order is located below the phylum. That means the organism with the same order should have more similarities than the organism with the same phylum. Those similarities are tightly correlated with the evolutionary relationship.
The image is not really helping since it was showing kingdom division, not the sequence of the taxonomic division.
