The parasite that causes malignant malaria in humans is Plasmodium falciparum. The sporozoites of Plasmodium enter the human body, when a female Anopheles mosquito bites a healthy person.
Life cycle of Plasmodium in human : 
(i)When the mosquito bites a man, sporozoites present in the salivary glands of female Anopheles mosquito are injected into the blood of the man
(ii) From the human blood, sporozoites enter the liver cells and grow in size to become a rounded schizont called cryptozoite. The latter divides to form cryptomerozoites.
(iii) The crypto-merozoite enters the human RBCs, and meta-cryptozoites are formed. The metacryptozoites divide to form meta-cryptomerozoites
(iv) In RBC, meta-cryptomerozoite becomes a rounded disc-like young trophozoite, which undergoes mitotic division to form multinucleate organisms, which give rise to merozoites
(v) Some erythrocytic merozoites enter fresh RBCs and form rounded gametocytes. When female Anopheles mosquito sucks the blood of human, gametocytes enter the stomach of the mosquito

Darwin was influenced by Thomas Malthus and his book" An essay on the principles of population" in which he discussed that there are 'positive checks' that control geometrically growing population. The work of Malthus on human population growth infact influenced him. 

(i) (a) Species  A group of specific organisms with similar characteristics which are capable of compatible interbreeding to produce fertile offsprings
(b) Niche The way in which an organism functions in relation to the biotic and abiotic factors within its habitat that serves a purpose in its environment.
(ii) Increased selection pressure due to climatic or habitat change cause organisms to become specialised and have the optimum phenotype that is suited to the prevailing environment condition.
In the primary radiation, the six closely related species evolved as a result of the increasing water levels when the lake first filled. This change in the environment exerted a selection pressure on their river dwelling ancestors to adapt by developing different characteristics for survival, thus giving rise to the six species that could occupy more niches.

The multiple identical copies of specific template DNA can be produced by DNA cloning. It can be carried out by the use of a vector to carry specific foreign DNA fragment into the host cell. The mechanism of cloning and transfer of a gene for human growth hormone into
E. coil is diagrammatically represented below:

During changing weather, one is advised to avoid crowded places because changing seasons are the time when infectious agents are more active as moist conditions favours the growth of pathogens. Also, people are more vulnerable as their body system is busy in adapting the changing environmental conditions of temperature, humidity, etc.
Thus, getting easily infected by these pathogens.

Ontogeny is embryonic development, i.e. the origin and development of an organism from an embryo to an adult.
Phylogeny is ancestral history, i.e. the evolutionary development and history of a species or higher taxonomic grouping of organisms.                                     

Withdrawal syndrome.
These are the characteristic and unpleasant manifestations of the body,when regular dose of drugs/alcohol is abruptly discontinued.
Characteristics:
(i) Anxiety        
(ii) Excess sweating      
(iii) Shakiness  
(iv) Nausea.
In some cases withdrawal symptoms can be severe and even life-threatening.

A patent refers to the exclusive rights over any idea or invention. In case of biology, this patent is called biopatent. The main purpose of introducing patenting in biology is to ensure that there is financial security to the investors The major abuse of biopatenting is that large profits can be made by charging royalties or hiking up prices for their inventories. These may not be fulfilled by other

1. At high altitude places, one may experience altitude sickness, as the atmospheric pressure is low and the body does not get enough oxygen.
2. But gradually the body gets acclimatised by increasing the red blood cell production, increasing the breathing rate and decreasing the binding affinity of haemoglobin.

Addition or deletion 1 or 2 chromosomes is aneuploidy (2n+1, 2n-2). Addition of 1 or more complete sets of chromosomes is polyploidy (3n, 4n).

Features that characterise AIDS
1.Lymphopenia 
2.Selective cell deficiency
3.Polyclonal activation of Bulls and increased spontaneous secretions of lg.
4.Decreased cyctotoxic responses by T-cells.
5.Decreased antibody response to new antigens.
6.Altered monocycte/macrophage function

RNA pathogenic viruses are more mutable because RNA is less stable biomolecule than DNA.RNA is single stranded with no complimentary nucleotide pairing.So the nucleotides are readily affected by mutagenic factors.

(a) (i) Sporozoite
(ii) Gametocytes
(b) Sexual reproduction occurs in mosquito's intestine.
Asexual reproduction occurs in human body, in the liver cells and red blood cells.
(a) (i) Addiction refers to the psychological attachment to certain effects of drugs/alcohol.
(ii) Dependence refers to the tendency ofthe body to manifest a characteristic, unpleasant symptoms if regular dose of the drug/alcohol is abruptly discontinued.

Hallucinogens are drugs that cause an alternation in the perception thought and mood. Several plants, fruits and seeds that have hallucinogenic properties have been used for hundreds of years in folk medicine, religious ceremonies. Hallucinogens are being studied for possible medicinal uses but most of the treatments by hallucinogens have been banned. Examples of hallucinogens are LSD, amphetamines, marijuana.

(i) No, the belief of the people that insects and moths might have developed from the mud is wrong. The theory of origin of life in such a way is known as the theory of spontaneous generation or which was disproved by many scientists.
(ii) Life comes from pre-existing life only. The insects have not developed abiogenetically but they have
developed from the fertilized eggs lying in the mud.
(iii) Values exhibited-

• Awareness about the environment
• Understanding
• Disposal of myths and wrong belief prevailing in the society.

(i) Golden rice is variety of rice in which rice grain has a coating of beta carotene, a precursor of vitamin A.
(ii) It is very useful for poor rice eating human population which generally suffers from vitamin A deficiency.
(iii) Being a farmer, Anil's grandfather was concerned about the latest development in agriculture and wanted to grow such varieties which provide better nutrition contents to human beings.

Evolution on the grand scale of geological time, is called macroevolution while evolution at genetic level is micro-evolution. Micro-evolution is actually is actually operative at genetic level change.
Significance of Population Genetics: The gene frequency of a population is called population genetics. Evolution occurs within populations as the relative frequencies of different variations of DNA change over time. If genes change the enzymes automatically change and represent two different forms of individuals and definitely result in evolution.

Transgenic animals Transgenic animals are produced for the following purposes:
(i) Transgenic animals are designed to allow the study of how genes are regulated and how they affect the normal functions of the body and its developments e.g. Information is obtained as to how insulin has a role as growth factor.
(ii) Transgenic animals are designed to increase our understanding as to how genes control the development of diseases; they serve as models for human di eases.
(iii) Transgenic animals that produce useful biological compounds lure created by introducing a portion of the DNA that codes for that product, e.g.
\(\alpha \) -I antitrypsin is produced for curing emphysema.
(iv) Transgenic mice are being developed to test the safety of vaccines. e.g., polio vaccine has been tested on mice.

(i) (d)
(ii) (a)
(iii) (d)

(i) IgE antibody is released in allergic reactions.
(ii) Watery eyes, running nose, wheezing, sneezing, etc.
(iii) Adrenaline and steroids help to suppress and serotonin from the mast cells upon the entry of allergens in body. Thus, the allergic symptoms are either suppressed or reduced.
(iv) Autoimmune diseases are those in which the body begins to attack self-cells, e.g. rheumatoid arthritis, Addison's disease, etc.
(v) There are no permanent cures for autoimmune histamine diseases, but standard treatments available to reduce the signs and symptoms to a certain level.

(b) If both Assertion and Reason are true but Reason is not the correct explanation of Assertion.
Explanation:
Innate immunity refers to nonspecific defense mechanisms that come into play immediately or within hours of an antigen’s appearance in the body. Four barriers are physical, physiological, cellular and cytokine barriers.

(d) If A is false, but R is true