Which of the following does not have any place in the ecological pyramids?

Common cold is caused by:

In order to link the alien DNA, the vector needs to have very few, preferably single, recognition sites for the commonly used restriction enzymes. Presence of more than one recognition sites within the vector will generate several fragments, which will complicate the gene cloning. In Biolistics or gene gun method cells are bombarded with high velocity micro particles of gold or tungsten coated with DNA. The ligation of alien DNA is carried out at a restriction site present in one of the two antibiotic resistance genes. For example, you can ligate a foreign DNA at the BamH I site of tetracycline resistance gene in the vector pBR322. Since the DNA is enclosed within the membranes, we have to break the cell open to release DNA along with other macromolecules such as RNA, proteins, polysaccharides and also lipids. The RNA can be removed by treatment with ribonuclease whereas proteins can be removed by treatment with protease. Other molecules can be removed by appropriate treatments and purified DNA ultimately precipitates out after the addition of chilled ethanol.
Which one of the following statements is correct with reference to biolistics?

In gel electrophoresis, the separated DNA fragment can be visualized -

Recombinant DNA technology involves the following steps in a specific sequence.
(A) Culture of the host cell
(B) Extraction of desired product
(C) Isolation of desired DNA fragments
(D) Transformation of the recombinant DNA into the host cell Arrange these sequences correctly and choose the correct answer from the options given below:

What does 'r' denotes in the given equation?
(dN/dT = rN)

Read the given paragraph and answer the question:
Humans have 23 pairs of chromosomes. 22 pairs are exactly same in both males and females; these are the autosomes. A pair of X-chromosome are present in the female, whereas the presence of an X and Y chromosome are determinant of the male characteristic.
A number of disorders in human beings have been found to be associated with the inheritance of changed or altered genes or chromosomes. Broadly, genetic disorder may be grouped into two categories-Mendelian disorders and Chromosomal disorders.
A haemophilic man marries a normal woman. What is the possibility that their child have haemophilia?

The particular solution of the differential equation \(x\left(1+y^2\right) d x-y\left(1+x^2\right) d y=0\), given that \(y(0)=1\) is :

The focal length of the objective of a compound microscope is \( f_o \) and its distance from the eyepiece is L. An object is placed at a distance u from the objective. For proper working of the instrument
(A) L < u
(B) L > u
(C) \( f_o < L < 2f_o \)
(D) L > \( 2f_o \)
Choose the correct answer from the options given below:

If the maximum value of the function \(f(x)=\frac{2 \log _e x}{x}, x>0\) occurs at \(x=e\), then \(e^3 f^{\prime \prime}(e)\) is equal to

For a coil of 5 turns, the magnetic flux varies with time as \( \phi_{B}(t) = (2t^3 - \frac{5}{2}t^2 + t) \), where \( \phi_{B}(t) \) and t are in S.I. units. The induced current at t = 2 s in the coil, if its total resistance is 150 \( \Omega \), is :

Bone structure of forelimbs of vertebrates like whale, bat, cheetah and human is evidence of:

Which of the following is not a part of combined diversity at all levels of biological organisation as given by Edward Wilson ?