Identify the statement which do not hold true for Deoxyribose Nucleic Acid.
A. Only purine bases are present in DNA.
B. Deoxyribose sugar is present
C. A nitrogenous base is linked to the \(1^{\prime} C\) pentose sugar through N- glycosidic linkage.
D. Phosphate group is linked to OH of \(4 ^{\prime} C\) of a nucleotide.
Choose the correct answer from the options given below:

When red and white flowered parents of snapdragon were crossed, the phenotypic ratio of F2 generation would be:

Jawless fish probably evolved around:

The process through which spermatids are transformed into spermatozoa (sperms) is known as:

Read the following passage carefully and answer the given questions.
Immune System in the Body
The human immune system consists of lymphoid organs, tissues, cells and soluble molecules like antibodies. The primary lymphoid organs are bone marrow and thymus where immature lymphocytes differentiate into antigen-sensitive lymphocytes. After maturation the lymphocytes migrate to secondary lymphoid organs like spleen, lymph nodes, tonsils, Peyer's patches of small intestine and appendix. The secondary lymphoid organs provide the sites for interaction of lymphocytes with the antigen, which then proliferate to become effector cells. The bone marrow is the main lymphoid organ where all blood cells including lymphocytes are produced. Each antibody molecule has four peptide chains, two small called light chains and two longer called heavy chains. Hence, an antibody is represented as H2L2. Different types of antibodies are produced in our body. IgA, IgM, IgE, IgG are some of them. 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.
Maturation of lymphocytes takes place in:

The female reproductive system consists of :
(A) Ovaries
(B) External genitalia
(C) Cervix and vagina
(D) Oviducts and uterus
Choose the most appropriate answer from the options given below:

The detritus food chain (DFC) has at the first tropic level.

Match List - I with List - II.

List - I	List - II
(A) Insulin	(I) Carbohydrate metabolism
(B) Glucocorticoids	(II) Controls blood sugar level
(C) Mineralocorticoids	(III) Low level of thyroxine
(D) Hypothyroidism	(IV) Control levels of excretion of salt

Choose the correct answer from the options given below :

Which of the following are examples of irregular trends in a time series?
(A) Decrease in production due to a sudden strike.
(B) The rise in prices before festivals.
(C) Unusual rise in income of the printing press due to the announcement of an election.
(D) Fall in crop yield due to floods.
Choose the correct answer from the options given below :

Insulin keeps glucose level within the narrow limit. It is released in response to the rapid rise in blood glucose level. The hormone that tends to increase glucose level in the blood is :

What is the formula of following coordination compound: Potassium trioxalatoaluminate(III)

When aniline is reacted with benzoyl chloride, the correct product is

The area (in square units) of the region enclosed between the lines \(x+y=2, x=0, x=3\) and \(x\) - axis is equal to