After gastrulation in sea urchins, identify the cells that remain on the surface.Multiple choice question.MesodermEndodermEctodermBlastocyst

Which of the following statements concerning animal gastrulation is correct?Group of answer choicesCells from the blastomere cannot become mesodermal cells.Three germ layers are created; the endoderm, mesoderm and epidermis.The endoderm develops into the gut and lungs.The mesoderm develops into the muscles and nervous system.

In birds, cells that migrate through the primitive streak into the interior of the embryo become which of the following germ layers?Multiple choice question.Mesoderm or ectodermEctoderm or endodermEndoderm or mesoderm

Which of the following best describes how the sperm nucleus enters the egg in sea urchins?Multiple choice question.The acrosomal process extends through the egg's vitelline envelope to the egg's plasma membrane to allow the sperm nucleus to pass through to the egg.The sperm head burrows through the zona pellucida to the egg, and the sperm nucleus passes directly into the egg cytoplasm.

Which of the following tissues arise from the mesenchyme

What type of cells surround the body of a sponge?Multiple choice question.AmoebocytesEpithelial cellsSpiculesChoanocytes