Select the correct statement/s from the following:
A. Spermatogonia always undergo meiotic cell division.
B. Primary spermatocytes divide by mitotic cell division.
C. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division
D. Spermatozoa are transformed into spermatids.
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The bond between two successive nucleotides in RNA is

Identify the invasive plant species posing threat to native species.
(A) Parthenium
(B) Clarias
(C) Eicchornia
(D) Lantana
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Arrange the following events of embryo development occuring after fertilisation in the correct sequence.
A. Attachment of blastocysts with uterine endometrium
B. Formation of morula
C. Formation of blastocyst
D. Cleavage in the zygote
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Read the passage carefully and give the answers to the question :
India was amongst the first countries in the world to initiate action plans and programmes at a national level to attain total reproductive health as a social goal.
These programmes called 'family planning' were initiated in 1951 and were periodically assessed over the past decades. Improved programmes covering wider reproduction-related areas are currently in operation. Creating awareness among the people about various reproduction-related aspects and providing facilities and support for building up a reproductively healthy society are the major tasks under these programmes.
Which of the following statements is incorrect with respect to Medical Termination of Pregnancy?

After industrialization in 1920 in England, the proportion of dark winged and white winged moths reversed because of:

Which is not the salient feature of human genome project-

The area bounded by \(y^2=x, y=5\) and the \(y\)-axis is:

Read the passage carefully and answer the Questions
A homogeneous mixture of two or more than two components has uniform composition and properties. The binary solutions have two components, which may be solid, liquid or gas. The resultant solution has a larger amount of solvent and a smaller amount of solute. The amount of solute in a given amount of solvent decides the concentration of the resulting solution. The concentration can be expressed in various ways, like molarity, molality, normality and mole fraction. The molality of a 1 liter aqueous solution of \(93 \backslash \% H _2 SO _4\) (mass/volume) is:
(Given: density of the solution \(=1.84 g mL ^{-1}\), molar mass of \(\left.H _2 SO _4=98 g mol ^{-1}\right)\)

Analogous structures are formed as a result of :

Answer the question on the basis of passage given below :
All transition elements display typical metallic properties like high melting point, boiling point, tensile strength, high malleability and ductility, luster, etc. Their metallic character increases down the group and elements of \(4 d\) and 5d series exhibit higher metallic characters. They show variable oxidation states and forms a number of coloured compounds due to the presence of unpaired electrons which shows d-d transitions and makes them paramagnetic.
Which of the following will be coloured in aqueous medium?

Match List-I with List-II

List-I (EM waves)	List-II (Application)
(A) Infrared	(I) diagnostic tool in medicine
(B) X-rays	(II) water purification
(C) UV rays	(III) communication radar
(D) Microwaves	(IV) improving visibility in foggy days

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A yellow LED of power 0.2 W emits light uniformly around it. The amplitude of the electric field of light at a distance of 2 m from the LED is: