Blastula forms after successive meiotic divisions of an egg

Blastula forms after successive meiotic divisions of an egg increase in the size of the blastomeres increase in the number of blastomeres one of the various types of gastrulation processes none of the above In a frog, separation of the cells of a two-cell stage embryo may lead to the production of twins, which in this case would be identical of different sexes fraternal partially formed, each representing a half-embryo The three germ layers are formed in the Amphioxus mainly by involution invagination ingression epiboly b & c all of these In Amphibian the formation of the yolk plug results from of cells toward the blastopore. involution, ectodermal epiboly, ectodermal invagination, endodermal a & b b & c The primary difference in the frog and chicken eggs that so drastically affect their early cleavage pattern is the size of the ovum size of the sperm the shape of the egg the amount of yolk the presence of a shell rather than a jolly coat. In mammalian embryos, the inner cell mass develops into the placenta snail projections called villi the umbilical cord the embryo a & c The formation of gastrula results in the presence of a blastopore and gastrocoel. results in a hollow ball of cells results in the differentiation of endoderm and ectoderm a & c a, b & c In vertebrates, the liver, pancreas and gall bladder are derived from ectoderm endoderm mesoderm a combination of these

Solution

1. The blastula is 32-celled hollow structure that is formed after a zygote undergoes cell division. The rapid, multiple rounds of cell division are termed cleavage. After the cleavage has produced over 100 cells, the embryo is called a blastula. The blastula is usually a spherical layer of cells (the blastoderm) surrounding a fluid-filled or yolk-filled cavity (the blastocoel).