The transport of soluble products of photosynthesis is known as translocation. Translocation in plants occurs by means of the vascular tissue known as phloem. Translocation is necessary because without it, the food prepared by the leaves cannot reach other parts of the plant.
(i)In plants, the synthesis of sugars takes place in the leaves by the process of photosynthesis.
(ii)Hormones are synthesised away from their targrt site.

(i)The glottis is gaurded by epiglottis because it prevents the entry of food in wind pipe. If the food enters wind pipe, then it chokes it, leading to the death of the person.
(ii)The lung alveoli are covered with blood vessels because the oxygen that we inhale dissolves in the blood, present in these blood capillaries only, as it reaches the lungs.
(iii)The wall of trachea is supported by cartilage rings because these rings prevent the air passage from collapsing.

(i)Bile is helpful in the emulsification of fats i.e., the breaking down of large fat droplets into smaller fat globules, which the pancreatic enzymes can act upon.
(ii)The pancreatic juice contains enzymes that require an alkaline medium to act. The bicarbonate secreted by the duodenum provides this alkaline medium.
(iii)The function of pancreatic amylase is to convert complex carbohydrates into glucose, which is absorbed in the blood.

(i) Oxygen enters the human body through the nasal passage and reaches the lungs.
(ii) Numerous alveoli are present in the lungs. These alveoli are surrounded by many blood capillaries. From the alveoli, 0₂ is taken up by the red blood cells present in the blood capillaries.
(iii) Similarly, the CO₂ from the various tissues is transported to the alveoli.
(iv) This CO₂ is then released through the nasal passage during exhalation. Alveoli are the sites of exchange of gases. Each lung contains 300- 350 million alveoli.
These alveoli increase the surface area for gaseous exchange, making the process of respiration more efficient.

Carbon based molecules, i.e. food is used by body to meet its energy nced. Oxygen is used to oxidise food which release energy. Water is requircd for operating most of the functions inside the body. So, food, water and oxygen are the basic raw materials used by an organism.

(i)Removal of waste products from the blood
(ii)Maintenance of the water balance of the body
The procedure used in the working of artificial kidney is haemodialysis.

Oxidation-reduction reaction

Blood flow will increase upon the pressure of blood in the blood vessels. The oxygenated blood flowing through the artery doesnot have any impact as the arteries are thick walled, highly elastic blood vessels having narrow lumen and no valves.

Enzymes produced by salivary glands:
There are three major parts of salivary glands that secrete saliva with the digestive enzyme such as parotid, submandibular and sublingual glands.
They secrete saliva in the oral cavity which contains some enzymes like amylase, lysozyme, and lingual lipase.
Amylase works on carbohydrates like starch and converts them into maltose.
Lysozyme kills bacteria present in the mouth by destroying their cell walls.

The blood vessels which carry blood from organs to the heart are veins.

Translocation

(i) Cloudy Days As on a cloudy day, there will be less sunlight, the rate of photosynthesis will decrease because sunlight is necessary for photosynthesis.
(ii) No Rainfall in the Area The rate of photosynthesis willdecrease because water is one of the raw material needed by plants for photosynthesis. If there is no rainfall in an area, there will be less water available to plants.
(iii) Good Manuring in the Area The rate will increase because plants need raw minerals such as nitrogen, phosphorus, iron and magnesium, etc. for their growth and take these minerals from the soil. Good manuring in the area will increase the amount of
these minerals in the soil, thus increasing the rate of photosynthesis.
(iv) Stomata get blocked due to dust The rate will decrease because carbon dioxide gas required for photosynthesis enters the leaves through the stomata. If the stomata gets blocked due to dust, less or no carbon dioxide would enter the leaves, the rate
of photosynthesis will drop.

The major events during photosynthesis are
(i)absorption of light energy by chlorophyll
(ii)Conversion of light energy to chemical energy
(iii)splitinh of H₂,O₂ and e^-
(iv)reducing of CO₂ to carbohydrates

The functioning of alveoli in the lungs and nephrons in the kidneys is compared below

The necessary conditions for autotrophic nutrition are:
(i) water
(ii) carbon dioxide
(iii) sunlight
(iv) chlorophyll
The byproduct of autotrophic nutrition is oxygen, which is released into the atmosphere through stomata.

Photosynthesis is the process by which plant cells prepare food (carbohydrates) from inorganic raw materials such as carbon dioxide and water in presence of sunlight and chlorophyll.
\({ 6CO }_{ 2 }+{ 6H }_{ 2 }O\xrightarrow [ Chlorophyll ]{ Sunlight } { C }_{ 6 }{ H }_{ 12 }{ O }_{ 6 }+{ 6O }_{ 2 }\)
The process of photosynthesis takes place in two phases:
Light reaction - It requires light which is absorbed by chlorophyll molecules to split water molecules into hydrogen and oxygen. ATP and NADPH₂ are produced during this phase and it occurs in the thylakoid membrane of the chloroplasts.
Dark reaction - It does not require light energy and it occurs in the stroma of chloroplasts, In this phase, the ATP and NADPH₂ formed during light reaction are utilised and CO₂ is reduced to form carbohydrates.
The four factors affecting the rate of photosynthesis are:
(i) Sunlight - Sunlight provides the energy required for the preparation of food by plants. In the absence of sunlight, photosynthesis cannot take place.
(ii) Carbon dioxide - Carbon dioxide acts as the substrate for photosynthesis. During this process, carbon dioxide and water are converted into carbohydrates.
(iii) Water - During photosynthesis, water is photolysed into oxygen and hydrogen and it provides the energy for photosynthesis.
(iv) Chlorophyll - Chlorophyll is the green pigment present in the leaves which absorbs sunlight

The mechanism of urine formation includes three steps namely,
(i) Glomerular ultra-filtration
(ii) Tubular reabsorption
(iii) Tubular secretion
(i)Glomerular Ultrafiltration:
Ultrafiltration of blood takes place inthe Malphighian body which acts as a biological filter. A Malphighian body comprises of Bowman's capsule and glomeruli.
The blood from the kidney flows through the capillaries of glomerulus where the blood pressure, is comparatively high and so brings about effective filtration. The hydrostatic pressure of the blood is always greater than the opposing pressures existing in the plasma protein and renal capillaries. Thus, the available net filtering force is chiefly responsible for glomerular filtration. The fluid in the capsule which is obtained by this process is termed glomerular filtrate. In man it is about 125ml/min. In 24 hours, the total volume of glomerular filtrate is 170 to 180 litres.
(ii) Tubular Reabsorption: Reabsorption takes place in the 'uriniferous tubules. Reabsorption of useful substances is a differential or selective process. The glomerular filtrate contains many useful substances such as glucose, amino acids, mineral salts and vitamins dissolved in large amount of water. Substances such as glucose, sodium and calcium, are actively reabsorbed in large quantities. Substances like urea and uric acid etc are reabsorbed in small quantities by a simple diffusion process or passive reabsorption. Substances like creatinine are not reabsorbed. They are completely eliminated.
Proximal convoluted tubule is responsible for the reabsorption of water, glucose, sodium phosphate and bicarbonates. On entering the distal convoluted tubule, the urine becomes nearly isotonic to the surrounding tissue fluid due to the active transport of sodium and passive transport of water. As urine (isotonic) passes into the collecting tubule it becomes once again hypertonic by the osmotic reabsorption of water under the influence of the hormone ADH. Thus the urine formed contains 96% of water, 2% urea and 2% of the metabolic products.
(iii) Tubular Secretion: This is the final step in the formation of urine during which the walls of tubule actively remove additional waste substances which are harmful to the body from the blood that have escaped filtration.