1. Pacemaker is a medical device which uses electrical impulses, delivered by electrodes contracting the heart muscles, to regulate the beating of the heart.
2. The primary purpose of a pacemaker is to maintain an adequate heart rate, either because the heart's natural pacemaker is not fast enough, or because there is a block in the hearts electrical conducting system.

Cleistothecium, Perithecium, Apothecium and Pseudothecium.

The criteria adopted for the classification include cell structure, thallus organization, mode of nutrition, reproduction and phylogenetic relationship.

(i) Phosphorylation - Hexokinase, Phospho fructokinase and glyceraldehyde - 3 phosphate dehydrogenase
(ii) De-Phosphorylation - Phospho glycerate Kinase and Pyruvate Kinase

(i) Group A shows maximum photosynthesis. chlorophyll pigments of the spectrum is (400 - 450 nm), hence the photosynthesis is high.
(ii) Group B will show negligible amount of photosynthesis, because chlorophyll does not absorb any light in this region (500 - 550nm). It reflects green.

(i) Yes. Nitrogen cannot be directly absorbed by plants but they are essential for normal growth and functioning of a plant. Hence they are fixed by bacteria and some fungi.
(ii) It can be utilised only in the form of nitrates (NO₃^-) and nitrites (NO₂^-).

(1) Water potential \(\left(\Psi_{\mathrm{W}}\right)\) can be determined by,
(i) Solute concentration or Solute Potential \(\left(\Psi_{\mathrm{S}}\right)\)
(ii) Pressure potential \(\left(\Psi_{\mathrm{P}}\right)\)
(2) By correlating two factors, water potential is written as,
(3) Water potential = Solute potential + Pressure potential
(4) \(\Psi_{W}=\Psi_{S}+\Psi_{P}\)

The cells of sclerenchyma & tracheids become dead because they lack protoplasm

1. The ANS autonomic neural system is auto functioning and self-governed.
2. It is a part of the peripheral neural system that innervates smooth muscles, glands and cardiac muscle. This system controls and coordinates the involuntary activities of various organs.
3. ANS controlling centre is in the hypothalamus.

(i) Hormones coordinate different physical, physiological, mental activities and maintain homeostasis.
(ii) Maintenance of constant internal environment of the body by the different coordinating system.

Economic importance of prawn:
(i) Prawn is a very tasty proteinaceous food.
(ii) Economic growth can be achieved by prawn at a low cost.
(iii) It is profitable to cultivate prawns in fresh water at a low cost.
(iv) By Exporting prawns can also bring a lot of foreign currency to the country.

Actin, myosin, meromyosin, tropomyosin and troponin.

(i) A thin elastic flap called epiglottis is found in the upper respiratory tract.
(ii) It prevents the food from entering into the larynx.
(iii) It avoids choking of food.

1. Podocytes end in foot processes found in the openings between the foot processes (Filtration slits).
2. Malpighian body/renal corpuscle.
3. Blood cells like RBCs, WBCs and platelets.

(i) In stomach digested food is incompletely formed so that cannot be absorbed.
(ii) Finger like projections called villi are not found in the wall of stomach.
(iii) The concentration gradient by active transport cannot be created in stomach.

S.No.	Mitral Valve	semilunar Valve
1.	Found between left atrium and left ventricle.	Found at the entry of pulmonary artery and aorta.
2.	Has two flaps or cusps.	Has three flaps or cusps.
3.	Appear as flaps.	Appear as half moon shaped.
4.	Prevents the backword flow of oxygenated blood from left ventricle to left atrium.	Prevents the backward flow of deoxygenated blood into right ventricle and oxygenated blood into left ventricle.
5.	Also called as bicuspid valve.	Also called as pulmonary or aortic valves.

(i) Ommatidia are the visual units of compound eyes of cockroach.
(ii) Each ommatidium is functional as an eye unit.
(iii) Photoreceptors are dorsally found.
(iv) Each compound eye consists of 2000 simple eyes called ommatidia.
(v) All the visual images captured by ommatidia are made into a single coherent picture by supra oesophageal ganglion (brain).

White Adipose Tissue	Brown Adipose Tissue
1. Tissue contains less mitochondria.	Tissue contains more mitochondria.
2. Stores nutrients	Converts fats into heat energy which heat the blood stream to warm the body.
3. No non-shivering thermogenesis.	Non-shivering thermogenesis.

(i) Both the spongin and spicules are the components of exoskeleton of sponges.
(ii) A hard exoskeleton protects the animals from external environment.
(iii) Both the components are produced by scleroblasts.

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.

The word virus is derived from Latin meaning 'Poison' .

(i) Root climbers: Plants climbing with the help of adventitious roots (arising from node). Eg: Piper betel,Piper nigrum, Pothos.
(ii) Stem climbers: These climbers lack specialised structure for climbing and the stem itself coils around the Support. Eg: Ipomoea, Clitoria, Quisqualis.

Homoiomerous	Heteromerous
Algal cells evenly distributed in the thallus	A distinct layer of algae and fungi present

Nitrogenous base	Inorganic base
In nitrogenous base the basic character is because of lone pair electron called lewis base	Inorganic base is because of hydroxyl ion that is Arrhenius base
Eg: Pyridine, Pyrimidine	Eg: NaOH

(i) A beam of electron passes through the specimen to form an image. It provides two dimensional image.
(ii) The magnification is 1-3 lakhs times and resolving power is 2 - 10 Å.

Polypetalae: Plants with free petals and dichlamydeous flowers come under polypetalae. It is further divided into three series - (iii) Calyciflorae: It includes plant having flowers with cup shaped thalamus and with inferior or sometimes with half inferior ovary. It includes 5 orders and 27 families.

1. Genetic stability - Daughter cells are genetically identical to parent cells.
2. Growth - As multicellular organisms grow, the number of cells making up their tissue increases. The new cells must be identical to the existing ones.
3. Repair of tissues - Damaged cells must be replaced by identical new cells by mitosis.

Algae like Kappaphycus alvarezii , Gracilaria edulis and Gelidiella acerosa are grown commercially in the sea for harvesting phycocolloids got from cell wall of algae.

Xylem plates alternate with phloem plates. Eg: Lycopodium clavatum.