Ans. In protostele xylem surrounds phloem.
The type includes Haplostele, Actinostele, Plectostele and mixed protostele.
(i) Haplostele: Xylem surrounded by phloem is known as haplostele. e.g., Selaginella.
(ii) Actinostele: Star shaped xylem core is surrounded by phloem is known as actinostele. e.g., Lycopodium serratum.
(iii) Plectostele: Xylem plates alternates with phloem plates. e.g., Lycopodium clavatum.
(iv) Mixed prototostele: Xylem groups uniformly scattered in the phloem. e.g., Lycopodium cernuum.

S.No	Beneficial aspects	Bacteria	Role
1.	Soil fertility
	Ammonification		Bacillus ramosus	Convert complex proteins in the dead bodies of plants and animals into ammonia which is later converted into ammonium salt.
2.	Antibiotics
	Chloromycetin		Streptomyces venezuelae	Cures typhoid fever.
3.	Industrial use
	a) Cheese		Lactobacillus lactis	Convert milk to cheese.
	b) Vitamins		Escherichia coli	Produces Vitamin K and vitamin B complex in human intestine.
4.	Curing of Tea and Tobacco
			Bacillus megatherium	Adding special flavour and aroma to tea and tobacco leaves by fermentation.
5.	Diseases
	a) Bacterial blight		Xanthomonas oryzae	Affects rice crop.
	b) Cholera		Vibrio cholerae	Affects human beings.
	c) Anthrax		Bacillus anthracis	Affects sheep.

(i) R.H.Whittaker, an American taxonomist proposed five kingdom classification in the year 1969.
(ii) The Kingdoms include Monera, Protista, Fungi, Plantae and Animalia.
(iii) The criteria adopted for the classification include cell structure, thallus organization, mode of nutrition, reproduction and phylogenetic relationship. The merits and demerits are as follows:
Merits:
(i) The classification is based on the complexity of cell structure and organization of thallus.
(ii) It is based on the mode of nutrition.
(iii) Separation of fungi from plants.
(iv) It shows the phylogeny of the organisms.
Demerits:
(i) The kingdom Monera and Protista accommodate both autotrophic and heterotrophic organisms, cell wall lacking and cell wall bearing organisms thus making these two groups more heterogeneous.
(ii) Viruses were not included in the system.
 

i) This is also a slender, lateral branch originating from the base of the stem.
ii) But it first grows obliquely above the ground, produces a loop and bends down towards the ground. When touches the ground it produces roots and becomes an independent plantlet.
Example: Mentha piperita (peppermint), Fragaria indica (wild strawberry).

Cockroach carry with them harmful germs of various bacterial diseases like cholera, diarrhoea, tuberculosis, and typhoid and hence are known as "Vectors".

Vegetative reproduction includes fission in unicellular forms the cell divides mitotically to, produce two daughter cells. eg. Chlamydomonas.
Fragmentation: fragments of parent thallus grow into new individual. eg. Ulothrix.

Lack of food and favourable climate, food competition, non availability of water, interference of affect of predators elephants and other wild animals enter into human living area.

They are the small circular RNAs which are similar to viroids but they are always linked with larger molecules of the viral RNA. Discovered by J.W. Randles and Coworkers in 1981.

The special flavor and aroma of the tea are due to fermentation of Tea leaves by bacteria. Eg: Bacillus megatherium. This is called curing of Tea and Tobacco

The Nervous System: The blood consists of plasma [60%] and blood cells [40 %], red blood cells, white blood cells, and platelets. RBCs are loaded with red pigment, nucleated and oval in shape. Leucocytes are nucleated, and circular in shape (see figure). The Nervous system is divided into the Central Nervous System [CNS], the Peripheral Nervous System [PNS], and the Autonomous Nervous System [ANS]. Peripheral Nervous System consists of 10 pairs of cranial nerves and 10 pairs of spinal nerves. Autonomic Nervous System is divided into sympathetic and parasympathetic nervous system. They control involuntary functions of visceral organs.

They do not have photosynthetic pigment hence they cannot use sunlight energy. These type of bacteria obtain energy from organic or inorganic substance.
Mode of nutrition in Chemolithotrophs.
1. This type of bacteria oxidize inorganic compound to release energy
2. Examples
3. Sulphur bacteria Thiobacillus thiooxidans
4. Iron bacteria Ferrobacillus ferrooxidans
5. Hydrogen bacteria Hydrogenomonas
6. Nitrifying bacteria Nitrosomonas and Nitrobacter
Mode of nutrition in Chemoorganotrophs.
1. This type of bacteria oxidize organic compounds to release energy.
2. Examples
3. Methane bacteria - Methanococcus
4. Acetic acid bacteria - Acetobacter
5. Lactic acid bacteria - Lactobacillus

1. Eucoelom or true coelom is a fluid-filled cavity that develops within the mesoderm and is lined by mesodermal epithelium called peritoneum.
2. Such animals with a true body cavity are called eucoelomates
3. Based on the mode of formation of coelom, the eucoelomates are classified into two types,
i) Schizocoelomate animals - In these animals the body cavity is formed by splitting of mesoderm. Eg: Annelids, Arthropods, Molluscs.
ii) Enterocoelomate animals - In these animals the body cavity is formed from the mesodermal pouches of archenteron. Eg: Echinoderms, hemichordates and chordates.

1. Prions were discovered by Stanley B. Prusiner in the year 1982 and are proteinaceous infectious particles.
2. They are the causative agents for about a dozen fatal degenerative disorders of the central nervous system of humans and other animals.
3. For Eg: Creutzfeldt - Jacob Disease (CJD), I Bovine spongiform Encephalopathy (BSE) - commonly known as mad cow disease.