'Species richness contributes to the well being of an ecosystem' was explained through an analogy the rivet popper hypothesis'. The hypothesis was given by :

Which one of the following disease is not caused by bacteria?

The menstrual flow results due to:
A. Increased estrogen levels
B. When released ovum is not fertilized
C. When pregnancy occurs
D. Breakdown of the endometrial lining of the uterus and its blood vessels

Various types of skin colour in humans is an example of :

Arrange the following steps of retrovirus replication sequentially.
A. Production of viral DNA by reverse transcriptase
B. Introduction of viral RNA in host cell
C. Production of new viral RNA by host cell
D. Incorporation of viral DNA into host genome
Choose the correct answer from the options given below:

Bioactive molecule, cyclosporin A, that is used as an immunosuppressive agent in organ-transplant patients, is produced by the fungus -

Read the passage carefully and answer the questions given along
Our immune system plays the major role in preventing diseases when we are exposed to disease-causing agents. Immunity is of two types: (i) Innate immunity and (ii) Acquired immunity. The human immune system consists of lymphoid organs, tissues, cells and soluble molecules like antibodies. The immune system also plays an important role in allergic reactions, auto-immune diseases and organ transplantation. The primary lymphoid organs are bone marrow and thymus. The secondary lymphoid organs are spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix. There is lymphoid tissue also located within the lining of the major tracts (respiratory, digestive and urogenital tracts) called mucosa associated lymphoid tissue (MALT). It is important to note that HIV/AIDS is not spread by mere touch or physical contact; it spreads only through body fluids. AIDS has no cure, prevention is the best option. Adolescence is accompanied by several biological and behavioural changes and surveys and statistics show that use of drugs and alcohol has been on the rise especially among the youth. Factors associated with drug and alcohol abuse among adolescents are a child's natural curiosity, stress, the perception among youth that it is 'cool' or progressive to smoke, media exposure and an unstable or unsupportive family structures and peer pressure. It is best to identify the situations that may push an adolescent towards use of drugs or alcohol, and to take remedial measures well in time.
Which one of the following structures is not an example of a cellular barrier in innate immunity?

Read the following paragraph carefully and answer the given questions.
Certain types of leukocytes (WBC) of our body like polymorpho-nuclear leukocytes (PMNL-neutrophils) and monocytes and natural killer (type of lymphocytes) in the blood as well as macrophages in tissues can phagocytose and destroy microbes. For determining the cause of allergy, the patient is exposed to or injected with very small doses of possible allergens, and the reactions studied. The use of drugs like anti-histamine, adrenalin and steroids quickly reduce the symptoms of allergy. Heroin, commonly called smack is chemically diacetylmorphine which is a white, odourless, bitter crystalline compound. This is obtained by acetylation of morphine. Techniques like radiography (use of X-rays), CT (computed tomography) and MRI (magnetic resonance imaging) are very useful to detect cancers of the internal organs. Different species of Plasmodium (P. vivax, P. malaria and P. falciparum) are responsible for different types of malaria. Of these, malignant malaria caused by Plasmodium falciparum is the most serious one and can even be fatal.
Heroin, commonly called smack is chemically _________ which is a white, odourless, bitter crystalline compound.

Answer the question on the basis of passage given below :
One of the notable features of the transition element is the great variety of oxidation states it may show in its compounds. The elements which give the greatest number of oxidation states occur in or near the middle of the series. Manganese, for example exhibits all the oxidation states from +2 to +7. The lesser number of oxidation states at the extreme ends is either due to losing or sharing of few electrons (Sc, Ti) or too many d electrons of higher valence. Early in the first series scandium (II) is virtually unknown and titanium (IV) which is more stable than Ti (III) or Ti (II). On the other end, the only oxidation state of zinc is \(+ 2\).
Oxidation state of scandium is

The thermal decomposition of HI on gold surface is an example of

How many \(Cr-O\) bonds in dichromate ions are of the same bond length and are in resonance?

The function \(f(x)=x e^x\) increases only for:

Consider the following hypothesis \(H_0: \mu=315\) and \(H_a: \mu \neq 315\).
A sample of 60 provided a sample mean of 324.6 . The standard deviation ( \(\sigma\) ) is 14 and level of significance \(\alpha=0.05\). Then the confidence interval is :
[Given : \(Z_{\alpha / 2} \frac{14}{\sqrt{60}}=3.54\)]