(i) The first form of life could have come from pre-existing non-living organic molecules like RNA, proteins etc.
(ii) Formation of life was proceeded by chemical evolution that resulted in the formation of diverse organic molecules from inorganic constituents.

Bacterial (prokaryotic) RNA polymerase consists of two major components, the core enzyme and the sigma subunit. The core enzyme (\({ \beta }^{ 1 },\beta \) and \(\alpha\)) is responsible for RNA synthesis whereas a sigma subunit is responsible for recognition of the promoter.

The possible genotypes of a B-blood group person are I^BI^Bor I^Bl^O.

(i) Tubectomy is the surgical sterilisation method in women.
(ii) Vasectomy is the surgical sterilisation method in male.

The meiotic divisions I & II take place in order to ensure that the ovum is haploid since normal chromosomal number is important for formation of normal zygote. Further polar bodies have less cellular contents and are small since they do not participate in fertilization most of the cellular contents lie in the ovum.

Atropa belladonna and Datura

A - Monaxon spicules
B - Micropyle
C - Outer membrane
D - Archaeocytes
E - Inner membrane

The immune responses may be primary or secondary.
(i) The primary immune response occurs when a pathogen comes in contact with the immune system for the first time.
(ii) The secondary immune response occurs when a person is exposed to the same antigen again. During this time, immunological memory has been established and the immune system can start producing antibodies immediately. Within hours after recognition of the antigen, a new army of plasma cells are generated. Within 2 to 3 days, the antibody concentration in the blood rises steeply to reach much higher level than primary response. This is also called as "booster response".

Vatam, Pittam and Kapam.

Primary Introduction Secondary Introduction (i) No alternation of genes (i) Alternation by hybridization (ii) Adaptation capability is more (ii) Adaptation capability is more after hybridization

CSS - Carbon Capture and Storage.

There is a gradual decrease in energy transfer at successive tropic levels from producers to higher levels, hence the pyramid of energy is always upright.

Certain plants can also be used to remove cadmium from contaminated soil, this is known as phytoremediation.
Example: Eichhornia

1. The characteristic of soil that determines the movement of water through pore spaces is known as soil permeability.
2. Soil permeability is directly dependent on the pore size. Water holding capacity of the soil is inversely dependent on soil porosity.

1. Fertilizer runoff degrades aquatic eco system by promoting growth of algae, phytoplankton's and other aquatic plants.
2. A phenomenon called algal bloom will take place, by increasing oxygen consuming bacteria and lessening the available oxygen for plants and animals in the area.
3. Depletion of fish special general deterioration of water quality are the serious problems in aquatic eco system.

(i) PCR is a very sensitive technique which enables the amplification of desired DNA from a limited amount of DNA template.
(ii) A technique can be also used for amplifications of RNA in which case it is referred to as reverse transcription PCR (RT-PCR). In this process the RNA molecules (mRNA) must be converted to complementary DNA by the enzyme reverse transcriptase (reverse transcription).
(iii) The cDNA then serves as the template for PCR.
(iv) The specificity and sensitivity of PCR is useful for the diagnosis of inherited disorders (genetic, viral; bacterial, diseases).
(v) Hence, it can detect the presence of an infectious organism in the infected patient at an early stage of infection (even before the infectious organism has multiplied into large number).

There are three levels of biodiversity are
(1) Genetic diversity
(2) Species diversity and
(3) Community / Ecosystem diversity

(i) Biogas is a mixture of different gases produced by the breakdown of organic matter in the absence of oxygen.
(ii) The slurry is drained through another outlet and is used as fertilizer.
(iii) Biogas is used for cooking and lighting.

Name of the process-Plant tissue culture Types:
(a) Organ culture
(b) Meristem culture
(c) Protoplast culture
(d) Cell culture

(i) Darwin failed to explain the mechanism of variation.
(ii) Darwinism explains the survival of the fittest but not the arrival of the fittest.
(iii) He focused on small fluctuating variations that are mostly non-heritable.
(iv) He did not distinguish between somatic and germinal variations.
(v) He could not explain the occurrence of vestigial organs, over specialization of some organs like large tusks in extinct mammoths, oversized antlers in the extinct Irish deer, etc.,

Foeticide	Infanticide
It refers to aborting the female in the mother's womb.	It refers to killing the female child after her birth

Spirulina can be grown easily on materials like waste water from potato processing plants (containing starch), straw, molasses, animal manure and even sewage, to produce large quantities.

A - \(5^{\prime} \rightarrow 3^{\prime}\) is called a coding strand.
B - \(3^{\prime} \rightarrow 5^{\prime}\) is called a template strand.

In testes Sertoli cells secrete inhibin, a hormone which is involved in the negative feedback control of sperm production. (Spermatogenesis).

(i) A type of structural chromosomal abbrevation.
Reverse tandem duplication
(ii) The duplicated segment is located immediately after the normal segment but the gene sequence order will be reversed.

The genes present in the differential region of Y chromosome are called Y- linked or holandric genes. The Y linked genes have no corresponding allele on X chromosome. The Y linked genes inherit along with Y chromosome and they are phenotypically express only in the male sex.

Autoimmunity is due to an abnormal immune response in which the immune system fails to properly distinguish between self and non-self and attacks its own body. Our body produces antibodies (autoantibodies) and cytotoxic T cells that destroy our own tissues. If disease-state results, it is referred to as auto-immune disease.
Thus, autoimmunity is a misdirected immune response. Eg., Rheumatoid arthritis and multiple sclerosis

Offsprings produced by asexual reproduction are called clones, because they are genetically as well as morphologically similar to the parent organism.
They are not only similar to one another, but are also exact copies of their parent (e,g): Amoeba, Spirogyra, Hydra, Yeast, etc.

"Genetics" is the branch of biological science which deals with the mechanism of transmission of characters from parents to off springs.

Individuals formed by asexual reproductive methods are morphologically and genetically identical and are called clones.