Question

39. You observe that after one of the cells is removed from a developing embryo in an early (8-cell) stage, the remaining cells still develop into a completely normal organism. Which of the following is true regarding this organism?

-A. It is a protostome

-B. Zygotic cleavage is spiral

-C. Zygotic cleavage is radial

-D. It might be a mullusc

-E. It might be an annelid

40. Following gastrulation in vertebrates the mesodermal cells contribute to the developing

-A. Brain and nervous system

-B. Skeletal system and muscles

-C. Inner lining of the gut and respiratory tract

-D. Pigment cells

-E. Epidermis

Answer 1

E.

The annelids are capable of regeneration and so, even if a cell is removed from the embryonic stage, it develops into a full organism.

A.

The neural development takes place soon after gastrulation. Notochord develops from the mesoderm.