Androgens are synthesised and secreted by which of the following?

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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?

Myotonic dystrophy is an/a -

In an ecosystem, energy flow is:

Which of the following two STIs can be transmitted through contaminated surgical equipment and are not completely curable?

Alien DNA can be introduced into host cells by which of the following:
(A) Biolistics
(B) Micro-injection
(C) Cold-Shock
(D) Heat-Shock
Choose the correct answer from the options given below:

Match List I with List II.

LIST I	LIST II
A. Epidermophyton sp.	I. Typhoid
B. Haemophilus influenzae	II. Elephantiasis
C. Wuchereria malayi	III. Ringworm
D. Salmonella sp.	IV. Pneumonia

Choose the correct answer from the options given below:

The generalised communication system will have following essential components in sequence in a block diagram.
(A) Transmitter
(B) Channel
(C) Receiver
(D) Information source
(E) User of information
Choose the correct answer from the options given below :

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Nearly all the transition elements display typical metallic properties such as high tensile strength, ductility, malleability, high thermal and electrical conductivity and metallic lustre. The transition metals (with the exception of Zn, Cd and Hg) are very hard and have low volatility. Their melting and boiling points are high. They have high enthalpies of atomization. lons of the same charge in a given series show progressive decrease in radius with increasing atomic number. However, the variation within a series is quite small. The filling of 4f before 5d orbital results in a regular decrease in atomic radii called Lanthanoid contraction which essentially compensates for the expected increase in atomic size with increasing atomic number. The net result of the lanthanoid contraction is that the second and the third d series exhibit similar radii (e.g., Zr 160 pm, Hf 159 pm) and have very similar physical and chemical properties. There is an increase in ionisation enthalpy along each series of the transition elements from left to right. The first ionisation enthalpy, in general, increases, but the magnitude of the increase in the second and third ionisation enthalpies for the successive elements, is much higher along a series. One of the notable features of a transition elements is the great variety of oxidation states these may show in their compounds.
Metallic radii of some transition elements are as follows:
Fe: 126 pm; Co: 125 pm; Ni: 125 pm; Cu: 128 pm
Which of these elements will have highest density?

A bulb of \( 100 \text{ W} \) glows for \( 6 \text{ hours} \) a day. The units of energy consumed in \( 7 \text{ days} \) would be :

Which of the following matrices is not invertible?

Let \(y=\cos \left(\sin x^2\right)\), then the value of \(\frac{d y}{d x}\) at \(x=\frac{\sqrt{\pi}}{2}\) is equal to

Embryological support for evolution was disapproved by