In frog chromosome number is reduced to half
when 2nd polar body is separated
when 2nd polar body is divided
when 3rd polar body is separated
when 1st polar body is separated
D.
when 1st polar body is separated
Each primary oocyte undergo two maturation divisions, first meiotic and the second meiotic division.
In the I-meiotic division, the primary oocyte divides into two unequal haploid daughter cells - a large secondary oocyte and very small first polar body.
In II-maturation division, the first polar body may divide to form two second polar bodies. The secondary oocyte again divides into two unequal daughter cells, a large ootid and a very small second polar body. The ootid grows into a functional haploid ovum.
The I meiotic division is reductional and II meiotic division is equational division.
The figure shows different human tissues labelled as A to D. Which option gives the correct identification of the label, its location and one feature.
D-Unicellular glandular epithelium, goblet cells, secrete saliva
B-Squamous epithelium, walls of blood vessels, form a diffusion boundary
A-Cuboidal epithelium, ducts of glands, secretion and absorption
C-Columnar epithelium, lining of stomach, secretion and absorption
Pacinian corpuscles occur in the skin of certain parts of body in mammals. These are
type of glands
pain receptors
naked tactile receptors
encapsulated pressure receptors.
Pseudostratified epithelium is found in
seminiferous tubule
Fallopian tube
trachea
kidney tubules
Assertion : Gap junctions perform cementing function to keep the neighbouring cells together.
Reason : Tight junctions facilitate the cells to communicate with each other by connecting the cytoplasm of adjoining cells, for rapid transfer of ions, small and big molecules, etc.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false
If both assertion and reason are false
Assertion : A mutual exchange of sperms occurs between two earthworms during mating.
Reason : Mature sperms and egg cells and nutritive fluid are deposited in cocoons produced by gland cells of clitellum.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.
Microvilli of intestinal epithelium are similar in function with
typhlosole in earthworm
hepatic caecae in cockroach
intestinal caecum in earthworm
Malpighian tubules in coackroach
The type of epithelial cells which line the inner surface of Fallopian tubes, bronchioles and bronchi are known as
squamous epithelium
ciliated epithelium
columnar epithelium
cubical epithelium
Assertion : In cockroach respiratory gases directly comes in contact with the various organs of the body.
Reason : Cockroaches do not have respiratory pigment.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion : Pharyngeal nephridia play a role in the conservation of water in the earthworm.
Reason : They help the earthworm in keeping the skin moist for cutaneous respiration.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.