Each secondary spermatocyte after second meiotic division produces
four haploid spermatids
only one haploid spermatid
two haploid spermatids
two diploid spermatids
two diploid spermatids
C.
two haploid spermatids
A primary spermatocyte completes the first meiotic division (reduction division) leading to formation of 2 equal, haploid cells called secondary spermatocytes which have only 23 chromosomes each. Each secondary spermatocyte undergoes second meiotic division to produce two haploid spermatids.
Select the wrongly matched pair
Fibre - Sunhemp
Spice - Belladonna
Edible oil - Groundnut
Fodder - Trifolium
Fodder - Trifolium
The residual persistent nucellus in the seed of black pepper and beet is called
Perisperm
Endosperm
Pericarp
Scutellum
Scutellum
Consider the following statements with respect to flowering plants
(A) The pollen grains represent the male gametes
(B) The functional megaspore developing into the embryo sac represent the female gamete
(C) Transfer of pollen grains from anther to the stigma of different plant is known as xenogamy
(D) Transfer of pollen grains from anther to the stigma of another flower of the same plant is known as geitonogamy
Of the above statements
(A) and (B) alone are correct
(A) and (C) alone are correct
(A) and (D) alone are correct
(B) and (C) alone are correct
(B) and (C) alone are correct
Read the statements regarding a stable community and choose the correct option
(1) must be resistant to occasional disturbances
(2) should show much variation in productivity from year to year
(3) must be resistant to invasions by alien species
(1) and (2) are correct
(1), (2) and (3) are correct
(1) only is correct
(2) and (3) are correct
(2) and (3) are correct
Find the wrongly matched pair
Endemism - species confined to a region and not found anywhere else
Hot spots - Western ghats
Sacred groves - Jaintia hills of Rajasthan
ex situ conservation - Zoological parks
ex situ conservation - Zoological parks
The cytokine barrier among these is
Polymorphonuclear neutrophil
Monocyte
NK cell
Interferon
Interferon
Ringworms are caused by
I. Wuchereria
II. Microsporum
III. Haemophilus
IV. Epidermophyton
I and II
II and III
II and IV
I and IV
I and IV
Read the statements
(1) IgE antibodies are produced in an allergic reaction
(2) B-lymphocytes mediate cell mediated immunity
(3) The yellowish fluid colostrum has abundant IgE antibodies
(4) Spleen is a secondary lymphoid organ
Of the above statements
(1) only is correct
(1) and (2) are correct
(2) and (3) are correct
(3) and (4) are correct
(3) and (4) are correct
