Ascidians are also known as ......

• A) Cephalochordates
• B) Flat worms
• C) Tunicates
• D) Round worms

Sea urchin exhibit .......... pattern of cleavage.

• A) Holoblastic
• B) Radial
• C) Radial holoblastic
• D) Meroblastic

In snails, the resulting larva is callled .......

• A) Glochidia
• B) Trochophore
• C) Nymph
• D) Veliger

In sea urchin, the hyaline layer is made up of two layers: an outer lamina made primarily of hayline protein and an inner layer composed of .....

• A) Fibrinogen
• B) Fibronectin
• C) Fibropellin protein
• D) Fibrin

In snails, oocyte contain determinants which enter the 4D blastomeres and hence lead to the ........... for mesodermal and intestinal differentiation.

• A) Microblasts
• B) Mesentoblasts
• C) Meroblasts
• D) Osteoblasts

Gastrulation in snails is accomplished primarily by......

• A) Epiboly
• B) Ingression
• C) Invagination
• D) Involution

Ascidians belong to the phylum .......

• A) Mollusca
• B) Chordata
• C) Nematoda
• D) Arthropoda

Some snails have their coils opening to the left of their shells, called .......

• A) Super Coiling
• B) Spiral Coiling
• C) Daxtral Coiling
• D) Sinistral Coiling

The _________ is characteristic of several animal groups, including annelid worms, some flatworms, and most molluscs.

• A) Spiral holoblastic cleavage
• B) Radial holoblastic cleavage
• C) Rotational cleavage
• D) Bilateral holoblastic cleavage

The opening of the archenteron at the vegetal region is called the--------

• A) Blastopore
• B) Blastocyst
• C) Primitive gut
• D) Blastocoel

The cells adjacent to the chordamesoderm, the ------ cells, are the precursors of the mesodermal somites.

• A) Splanchnic mesoderm
• B) Intermediate mesoderm
• C) Axial mesoderm
• D) Paraxial mesoderm

In mammalian cleavage, --------------------- catches the blastocyst on an extracellular matrix containing collagen, laminin, fibronectin, hyaluronic acid, and heparin sulfate receptors.

• A) Perimetrium
• B) Endometrium
• C) Myometrium
• D) Uterus

The peripheral ring of blastoderm cells that have not shed their deep cells constitutes the -------------

• A) Area opaca
• B) Marginal zone
• C) Marginal belt
• D) Area pellucida

Discoidal meroblastic cleavage is present in _________.

• A) Reptiles
• B) Birds
• C) Fish
• D) Mammals

The yolk syncytial layer is formed at the -------------------, when the cells at the vegetal edge of the blastoderm fuse with the underlying yolk cell.

• A) 8th cell cycle
• B) 6th cell cycle
• C) 9th cell cycle
• D) 7th cell cycle

The bird egg is --------------------- with a small disc of cytoplasm sitting atop a large yolk.

• A) Telolecithal
• B) Mesolecithal
• C) Isolecithal
• D) Centrolecithal

The first cell movement of fish gastrulation is the epiboly of the ---------- cells over the yolk.

• A) Blastoderm
• B) Endoderm
• C) Mesoderm
• D) Ectoderm

....... is the type of cleavage in which only blastodisc becomes the embryo.

• A) Spiral
• B) Bilateral
• C) Discoidal
• D) Superficial

.......... is a type of cleavage that occurs in yolky eggs, like birds.

• A) Rotational
• B) Bilateral
• C) Spiral
• D) Meroblastic

In mammalian cleavage at 64-cell stage, the inner cell mass and the ------------- cells become separate cell layers, neither contributing cells to the other group.

• A) Blastula
• B) Trophoblast
• C) Blastocyst
• D) Mesentoblast