1. Aloin - a mixture of glucosides.
2. Its gel used as skin tonic.
3. Cooling effect and moisturizing effect helps in creams, lotions, shampoos, shaving creams, after shave lotions preparation.
4. Used has emollient, antibacterial, antioxidant, antifungal and antiseptic.

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

Because there is no effective light penetration & predominance of heterotrophs.

It is a technique of encasing seeds in a mixture of clay & soil humus & scattering them on to suitable ground, not planting of trees manually.

Sandy soil loses water at high rate, These characters along with other parameters such as p^H, mineral composition is also important.

(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.

Spermiogenesis Spermatogenesis lt is a process of formation of sperms from immature germ cells It is a process of transformation of a non-motile spermatid into a motile
spermatozoan Number of cells increased as each spermatogonium produces four spermatids No change in number of cells as only one spermatid develops into a spermatozoa

A diploid embryosac is formed from megaspore mother cell without a regular meiotic division
Example:
Eupatorium, Aerva

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

Advantages of seed dispersal:
1. Seeds escape from mortality near the parent plants due to predation by animals or getting diseases and also avoiding competition.
2. Dispersal also gives a chance to occupy favourable sites for growth.
3. It is an important process in the movement of plant genes particularly this is the only method available for self-fertilized flowers and maternally transmitted genes in outcrossing plants.
4. Seed dispersal by animals help in conservation of many species even in human altered ecosystems.
5. Understanding of fruits and seed dispersal acts as a key for proper functioning and establishment of many ecosystems from deserts to evergreen forests and also for the maintenance of biodiversity conservation and restoration of ecosystems.
Seed ball:
1. It is an ancient Japanese technique of encasing seeds in a mixture of clay and soil humus (also in cow dung).
2. It also includes the soil humus scattering them on to the suitable; not planting of trees manually.
3. This method is suitable for barren and degraded lands for tree regeneration and vegetation before monsoon period where the suitable dispersal agents become rare.

Structural difference between DNA and RNA.

DNA	RNA
It is double stranded with exception of some viruses	It is generally single stranded
It is the genetic material in all living organism	It is genetic material in some viruses only
The sugar is deoxy ribose (pentose)	The sugar is ribose (pentose)
Nitrogenous bases present are adenine, guanine, thymine and cytosine	Nitrogenous bases present are adenine, guanine, cytosine and uracil
It is less reactive, chemically and structurally more stable.	It is more reactive chemically and structurally less stable
It usually occurs inside the nucleus and in some cell organelles like mitochondria and chloroplasts.	Very little RNA occurs inside the nucleus. most of its found in the cytoplasm

Continuous variation Discontinuous variation Inheritance of phenotype is determined by the combined effects of many genes. The characteristics are controlled by one or two major genes which may have two or more allelic forms. Most of the characteristics exhibit a complete gradation, from one extreme to the other. Individuals produced by this variation show differences without any intermediate form between them. The variation may be due to the combining effects of environmental & genetic factors. They are unaffected by environmental conditions. This is also known as quantitative inheritance. This is also known as qualitative inheritance, E.g. Human height & skin colour E.g. Style length in Primula, plant height of garden pea.

Curcumin extracted from turmeric - yellow colour - good anti oxidant fight against cancer - anti inflammatory, anti diabetic, anti bacterial, antifungal and anti viral activities - stops platelets from clotting.

The differences between habitat and niche are as follows.

S. No	Habitat	Niche
1	A specific physical space occupied by an organism (species).	A functional space occupied by an organism in the same eco-system
2	Same habitat may be shared by many organisms (species).	A single niche is occupied by a single species.
3	Habitat specificity is exhibited by organism.	Organisms may change their niche with time and season

(i) Development of human society is inevitable. Natural habitats are destroyed for the purpose of settlement, agriculture, mining, Industries and construction of highways
(ii) As a result species are forced to adapt to the changes in the environment or move to other places. If not, they become victim to predation, starvation, disease and eventually die or results in human animal conflict.
(iii) Over population, urbanization, Industrialization and agricultural advancements require additional land, water and raw materials every year.
(iv) This is made possible only through fragmentation or destruction of natural habitats by filling wetlands, ploughing grasslands, cutting down trees, forest, desilting rivers, constructing transport ways, caving mountains, extracting, ores, changing the course of rivers and filling of seashore.

Human Ovum
a - Vitelline membrane
b - Nucleus
c - Zona Pellucida
d - Corona radiata

Semen or seminal fluid is a milky white fluid which contains sperms and the seminal plasma, which is secreted from the seminal vesicles, prostate glands and bulbo urethal glands or Cowper's gland.
The semen comprises of Fructose, ascorbic acid, zinc, cholesterol, protein, calcium, chlorine, blood group antigens, citric acid, DNA, magnesium, Vitamin B12, phosphorous, sodium, potassium, uric acid,lactic acid, nitrogen, and other nutrients for the sperms.

1. In Greek Parthenos means Virgin, Genesis means Produce.
2. Development of a haploid (n) egg into a complete individual without fertilization is known as parthenogenesis.
3. It was first discovered by Charles Bonnet in 1745.
4. Parthenogenesis occurs naturally in some invertebrates (e,g:) Nematodes, Water fleas, Scorpians, Parasitic (wasps).