Cells become variable in morphology and function in different regions of the embryo. The process is 
After formation of three primary germ layers (i. e., ectoderm, mesoderm and endoderm), cells of these three layers become variable in morphology, shape, size and more specified to form organs so as to meet out the future functional needs of the foetus, this process is called differentiation.
What is true about cells during cleavage?
No growth of the embryo occurs during cleavage because there is an increase in the number of cells and progressively they decrease in size.
Meroblastic cleavage refers to which type of division of egg? 
Meroblastic cleavage is a type of cleavage that occurs in very yolky eggs like birds in which the egg cytoplasm and not the yolk divides (incomplete division). There are two types of meroblastic cleavage, discoidal and superficial. Discoidal usually occurs in birds, reptiles, fishes etc. which have telolecithal eggs and superficial cleavage occurs in insects which have centrolecithal eggs.
Therefore, the correct answer is option B.
Eye lens is formed from
Eye is an organ which is derived from both ectoderm and mesoderm because lens,cornea,conjunctiva muscles of iris are ectoderm in origin. Whereas sclera,choroid, ciliary body, iris are mesoderm in origin.
Blastopore is the opening by which the cavity of the gastrula (gastrocoel), communicates with the exterior. It is formed as a result of invagination of endoderm during embryonic development. During maturation of some animals it evolves into the anus or the mouth; in others it is covered over and contributes to the canal joining the primitive gut with the cavity of the neural tube.
Termination of gastrulation is indicated by 
The process by which the blastula becomes a three-layered embryo, or gastrula, is called as gastrulation. During gastrulation, the embryo begins to approximate its body plan as cells arrange themselves into three distinct germ layers, or embryonic tissue layers: the outermost layer, the ectoderm; the innermost, the endoderm; and the mesoderm, which develops between them.
Additional cell divisions take place during gastrulation, and the germ layers become established through a combination of processes. Many cells lose their old cell-to-cell contacts and establish new ones through cell recognition and adhesion processes involving interactions among the integrins and other plasma membrane proteins and the extracellular matrix.
The simple type of gastrulation occurs in echinoderms and in amphioxus. Gastrulation begins when a group of cells at the vegetal pole undergoes a series of changes in shape that cause that part of the blastula wall to first flatten and then bend inward (invaginate). The invaginated wall eventually meets the opposite wall, obliterating the blastocoel. The embryo is converted into a double-walled, cup-shaped structure. The new internal wall lines the archenteron, the newly formed cavity of the developing gut.
The opening of the archenteron to the exterior, the blastopore, is the site of the future anus in deuterostomes. At first, the archenteron is a narrow slit, but it gradually expands at the anterior end of the embryo. As a result, the blastocoel progressively shrinks and eventually disappears, which marks the end of gastrulation.
In telolecithal egg, the yolk is found 
Eggs with abundant yolk concentrated in one hemisphere of the egg are termed telolecithal. This occurs in many invertebrates and in all vertebrates lower than marsupial mammals.
The amount of yolk and its distribution are changed in the egg. Which one is affected? 
What is true about cleavage in the fertilized egg of humans? 
In humans, the egg cleavage is homoblastic. Cleavage results in the production of cluster of cells, which is of the same size as that of zygote.
Cleavage is not identical to mitosis. The cleavage starts when the egg is in fallopian tube and not in uterus.
In an egg, the type of cleavage is determined by 
The amount of yolk and how it is distributed determines the type of cleavage. On this basis cleavage is of two types:
(a) Holoblastic - where the segmentation line passes through the entire egg. It occurs in alecithal (without yolk), microlecithal (with very little amount of yolk) and mesolecithal (little amount of yolk) egg.
(b) Meroblastic - where segmentation line does not pass through the egg and remained confined to a part of the egg. It occurs in megalecithal (large amount of yolk) egg.
The correct sequence in the process of development of human embryo is 
Fusion of male and female gamete produces a zygote. Repeated division of the zygote is called cleavage forming a solid morula. After further division and rearrangement a fluid filled cavity surrounded by blastomeres - blastula is formed. The appearance of germ layers mark the gastrula.
Which of the following processes is associated with a change in the cellular DNA amount? 
Cytokinesis involves division of the cytoplasm of the parent cell into its daughter cells. Fertilization involves the fusion of two haploid gametes. Blastulation refers to the process of cleavage in the zygote to form a blastula.
Exponential growth of cells is a characteristic feature of 
Therefore, the correct answer is option D.
Blastopore is the opening of 
Blastopore is the transitory opening on the surface of gastrula through which the internal cavity archenteron communicates with the exterior. It is formed by invagination of superficial cells during gastrulation.
During regeneration, modification of an organ to other organ is known as 
Epimorphosis is the replacement of a lost organ of the body by proliferating new cells from the surface of the wound or injured part.
What is true for cleavage? 
Cleavage involves repeated cell division without increase in size. But cell size decrease.
Vegetative propagation in mint occurs by: 
Sucker is a mode of vegetative propagation. It is a non- green slender stem branch which arises from the underground base of erect shoot or crown. It grows horizontally in the soil and ultimately comes out to form a new aerial shoot or crown. Each sucker has nodes with scale leaf and axillary bud. For example, mint has the sucker. It has adventitious root and scale leaf.
So, the correct answer is option A.
The “Eyes” of the potato tuber are 
The axillary buds of the potato tuber are called “eyes” in common language. They are found at the nodes of the stem tuber.
What is common between vegetative reproduction and apomixis?
Vegetative reproduction and apomixis both are asexual methods of reproduction, which gives the progeny genetically similar to parent.
Which one of the following is correctly matched? 
► Onion - Bulb - Underground stem,
► Ginger - Rhizome,
► Chlamydomonas - Zoospore,
► Yeast - ascospores
Select the wrong statement :
In oomycetes female gamete is large and non motile while male gamete is small & motile.
Monoecious plant of Chara shows occurrence of :
Monoecious or homothallic condition in Chara (green algae) is used to denote upper oogonium and lower antheridium on the same plant. The organisms, which possess both the reproductive organs are called bisexual. Unisexual condition represents both male or female organs in same organism.
Meiosis takes place in : [NEET 2013]
In diploid organisms, specialised cells called meiocytes(gamete mother cell) undergo meiosis. Conidia and gemmules are asexual reproductive structures found in penicillium and sponge respectively. Megaspores are female gametes in plants, which undergo sexual reproduction.
Syngamy can occur outside the body of the organism in
[NEET Kar. 2013]
In most aquatic organisms, such as a majority of algae and fishes as well as amphibians, syngamy occurs in the external medium (water) i.e., outside the body of the organism. This type of gametic fusion is called external fertilisation.
Which of the following animals are not viviparous?
The platypus is an oviparous mammal, which means that it lays eggs as its method of reproduction. Viviparous animals are those that give birth to live young, such as all placental mammals (like humans).