In water hyacinth, pollination is carried out by -
(A) Wind
(B) Water
(C) Insects
(D) Animals
Choose the correct answer from the options given below:

Introduction of which of the following on Galopagos islands caused extinction of Abingdon tortoise ?

Read the following passage carefully and answer the given questions.
The B-lymphocytes produce an army of proteins in response to pathogens. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Virus-infected cells secrete proteins called interferons which protect non-infected cells from further viral infection. Symptoms of allergic reactions include sneezing, watery eyes, running nose and difficulty in breathing. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Lymphoid organs are the organs where origin and/or maturation and proliferation of lymphocytes occur. The primary lymphoid organs are bone marrow and thymus. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix. Heroin commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine, which is extracted from the latex of poppy plant Papaver somniferum.
Interferons are produced by-

Verhulst-Pearl logistic growth equation can be represented by -

Alien DNA can be introduced in the animal host cell by :

The flowers which do not open at all are known as:

Which one is not the example of an invasive alien species?

If \(A=\left[\begin{array}{cc}3 & 2 a \\ 1 & 5\end{array}\right]\) and \(B=\left[\begin{array}{ll}2 & 3 \\ b & 5\end{array}\right]\) are singular matrices, then \(a+b\) is :

Which of the following statement(s) is/are true for p-type semiconductors?
(A) Holes are minority carriers and pentavalent atoms are the dopants.
(B) Electrons are majority carriers and trivalent atoms are the dopants.
(C) Holes are majority carriers and trivalent atoms are the dopants.
(D) Electrons are minority carriers and trivalent atoms are the dopants.
Choose the correct answer from the options given below:

Osmotic pressure of 0.02 M urea solution at \(27^{\circ} C\), is (given \(R=0.0821 atm L mol ^{-1} K^{-1}\) )

Progestasert and LNG-20 are examples of:

Answer the question on the basis of passage given below :
There are some deposits of nitrates and phosphates in the earth’s crust. Nitrates are more soluble in water. Nitrates are difficult to reduce under laboratory conditions, but microbes do it easily. Ammonia forms a large number of complexes with transition metals. Hybridisation easily explains the ease of sigma donation capability of NH₃ and PH₃. Phosphine is an inflammable gas, it is prepared from white phosphorus.
NH₃ is a stronger base than PH₃ because:

On simplifying \(\cot \left(2 \tan ^{-1} x\right)\) where \(|x|<1\), we get: