Phloem is the vascular tissue which transports food molecules to the place of necessity in the plant. The elements in the phloem are sieve elements, fibres, phloem parenchyma and companion cells. The transport in the phloem tissue is bidirectional. It forms vascular bundles in association with xylem .Phloem occupies the edges of the vascular bundle. 

Concave mirrors are used for many purposes. Some of them are:

1. Doctors use concave mirrors for examining eyes, ears, nose and throat.
2. Concave mirrors are also used by dentists to see an enlarged image of the teeth.
3. The reflectors of torches, headlights of cars and scooters are concave in shape.
4. Concave mirror shaped dishes of dish antennas are used to receive TV signals from satellites which are high up in the sky.

Excretory system

As result of cellular respiration, there are lots of gaseous and other forms of waste products produced within a body. These waste products need to be removed because they are toxic to the body. Excretion is the process of elimination of wastes produced within a body. Various systems in our body help in excretion such as kidney, lungs, skin, eyes, etc.

The heart is an organ which beats continuously to act as a pump for the transport of blood, which carries other substances with it. The human heart is divided into four chambers. The upper two chambers are called right and left atrium and the lower two chambers are called the right and left ventricles. Right atrium receives carbon dioxide-rich blood from the body. Blood from right atrium enters the right ventricle, which contracts and pumps the blood to the lungs. On the other hand, oxygen-rich blood from the lungs returns to the left atrium. From the left atrium, blood enters left ventricle. Left ventricle contracts and pumps the blood to all parts of the body. Hence, the rhythmic contraction and expansion of various chambers of the heart maintains the transport of oxygen to all parts of the body

Thrombosis is the formation of a blood clot, known as a thrombus, within a blood vessel. It prevents blood from flowing normally through the circulatory system.

Wind is the movement of air which depends on the difference in air pressure in the two regions. The greater the difference in air pressure the faster the air moves.

There are following situations:

1. Uneven heating between the equator and the poles: The regions close to the equator get the maximum heat from the Sun. The air in these regions gets heated and warm. The warm air rises in the equatorial regions of the earth creating an area of low air pressure and the cooler air from the regions in the 0–30 degrees latitude belt on either side of the equator moves in. This makes the wind to blow from the north and the south towards the equator. At the poles, the air is colder than that at latitudes about 60 degrees. The warm air at these latitudes rises up and the cold wind from the Polar Regions rushes in, to take its place. In this way, wind circulation is set up from the poles to the warmer altitudes. The winds would have flown in the north-south direction from north to south, or from south to north. A change in direction is however, caused by the rotation of the earth on its axis.
2. Uneven heating of land and water: The land near the equator of earth heats up faster than the water in oceans in summers. The air over the land gets heated and rises. This causes the winds to flow from the oceans towards the land. These are monsoon winds. The monsoon winds carry lot of water from the oceans and bring large amount of rains on land. The process in which the winds coming from the oceans carry a lot of water vapour and bring rains is a part of the water cycle in nature. The summer monsoon is very important to the farmers because most of the annual rainfall occurs at this time and helps in growing crops.

Forests are an important renewable natural resource. They are useful in the following ways:

1. Plants purify air by utilizing carbon dioxide in the atmosphere. They also maintain a balance between oxygen and carbon dioxide and prevent global warming on earth.
2. They provide food to wild animals directly or indirectly. Herbivores eat plants and carnivores prey upon herbivores.
3. They provide useful materials like firewood, timber, bamboo, wood for paper, gum, resin, fibre, honey, bee wax, bidi leaf, etc. They also provide spices like black pepper, cardamom, cinchona, cinnamon, etc.
4. Plants are a source of many medicines. Ayurvedic medicines are prepared from medicinal plants like tulsi, neem, jamun, turmeric, ginger, etc.

25 min=25*60=1500 sec

so distance= speed 8 time

=20 *1500 =30000 m=30 km

Wind is the movement of air which depends on the difference in air pressure in the two regions. The greater the difference in air pressure the faster the air moves.

There are following situations:

1. Uneven heating between the equator and the poles: The regions close to the equator get the maximum heat from the Sun. The air in these regions gets heated and warm. The warm air rises in the equatorial regions of the earth creating an area of low air pressure and the cooler air from the regions in the 0–30 degrees latitude belt on either side of the equator moves in. This makes the wind to blow from the north and the south towards the equator. At the poles, the air is colder than that at latitudes about 60 degrees. The warm air at these latitudes rises up and the cold wind from the Polar Regions rushes in, to take its place. In this way, wind circulation is set up from the poles to the warmer altitudes. The winds would have flown in the north-south direction from north to south, or from south to north. A change in direction is however, caused by the rotation of the earth on its axis.
2. Uneven heating of land and water: The land near the equator of earth heats up faster than the water in oceans in summers. The air over the land gets heated and rises. This causes the winds to flow from the oceans towards the land. These are monsoon winds. The monsoon winds carry lot of water from the oceans and bring large amount of rains on land. The process in which the winds coming from the oceans carry a lot of water vapour and bring rains is a part of the water cycle in nature. The summer monsoon is very important to the farmers because most of the annual rainfall occurs at this time and helps in growing crops.

The lens which is thinner in the middle than at edges is called concave lens. 

A concave lens always forms erect, virtual and smaller image than the object.

Indicators:  Indicators are substances that are used to test whether a substance is acidic or basic ot neutral in nature. They change their color when added to a solution containing an acidic or a basic substance.
Example: Turmeric gives brownish red color in basic medium and yellow in acidic medium.

Displacement is calculated as the shortest distance between starting and final point which prefers straight line path over curved paths.

Suppose a body is moving in two different directions x and y then Resultant Displacement will be

It gives the shortcut paths for the given original paths.

Here,

u = Initial velocity

v = final velocity

a = acceleration

t = time taken.

• Plants need water for absorbing nutrients from the soil for photosynthesis.
• Plants wilt and become dry in the absence of water.
• In the absence of water, plants may die and oxygen released by the plants may get depleted and thus causing the death of all organisms.

After fertilisation the zygote divides to form embryo. The fertilised ovule develop into a seed which contain embryo enclosed in a seed coat.As the seed grows the floral parts wither and fall off. Meanwhile the ovary grow in size and ripen to form fruit.

Ground water do not get polluted because it passes through the soil by the process of infiltration and gets accumulated in the water table.