Question

the hard structure is present in all embryos and may or may not be present in adults. the hard structure named as----​

Answer 1

Answer:

'Seed' is the right answer.

Answer 2

The hard structure is present in all embryos and may or may not be present in adults. the hard structure is named notochord.

• The notochord is a rod-like structure present in chordates and is the characteristic feature of chordates.
• In invertebrates, the notochord is replaced by the vertebral column.
• The notochord is cartilaginous and provides support to the body.
• In embryonic stages, notochord serves by secreting proteins such as hedgehogs for the development of surrounding tissue.
• In tunicates, notochord persists only in the embryonic stage whereas in lacelet it persists throughout the life.