Question

The early human embryo distinctly possesses
A. Gills
B. Gill slits
C. External ear (pinna)
D. Eyebrows

Answer 1

Hint: An embryo is an early stage of development of a multicellular organism. In general, in organisms that show sexual reproduction, embryonic development refers to the portion of the life cycle that starts just after fertilization and continues through the formation of body structures, such as cells, tissues, and organs.

Complete answer: Let us first discuss facts about chordates and human beings: Humans are chordates.
One of the primary and significant characteristic features of chordates is the presence of pharyngeal gill slits. It is not present in adult humans.

Humans are mainly intelligent primates on Earth. The scientific name of humans is Homo sapiens and the systematic position tells us that we are from the phylum Chordata. Chordate animals are characterized by the presence of four distinct structures:
1) notochord
2) pharyngeal gill slits,
3) post-anal tail and
4) dorsal hollow nerve cord.
Humans are Vertebrates and hence the features change a little. For example, the notochord is transformed into a vertebral column. Nerve cord is present dorsally and the post-anal tail is transformed into the reduced vestigial coccyx. But what about the gill slits- those are not present in adults though; still, this structure exists in human early embryos.

So, the correct answer is B. Gill slits

Note: Pinna is not present in humans, not even in the embryos as it has become degenerated over a period of time due to evolution. In the early embryo, eyebrows are also not formed.