The taxonomic category between kingdom and class is Phylum.
In humans, pharyngeal slits are presents in the embryo and develop into the the ears
The longitudinal halves of a chromosome that has undergone replication are known as chromatids. They will not be called chromosomes until after they are separated during Mitosis. Mitosis distribute the chromatids to daughter cells as a cell divides. The chromosomes are initially replicated in cells undergoing Meiosis, as in preparation for the mitotic division, but then, these chromosomes are divided twice so that four daughter nuclei are produced, each having the haploid chromosome number.
