The apical meristem is the growth region in plants found within the root tips and the tips of the new shoots and leaves. Apical meristem is one of three types of meristem, or tissue that can differentiate into different cell types. Meristem is the tissue in which growth occurs in plants.

Intercalary meristem is a type of meristematic tissue associated with the growth in length in the middle position, thus the name. In particular, it is made up of meristematic cells that divide mitotically in the stem at the base of nodes and leaf blades.

BIOSPHERE RESERVE (BR)

The International Co-ordinating Council (ICC) of UNESCO, November, 1971, introduced the designation ‘Biosphere Reserve’ for natural areas. The concept of Biosphere Reserves was refined by a Task Force of UNESCO’s MAB Programme in 1974, and BR network was formally launched in 1976.

Biosphere Reserve (BR) is an international designation by UNESCO for representative parts of natural and cultural landscapes extending over large area of terrestrial or coastal/marine ecosystems or a combination thereof.

Each Biosphere Reserves are protected areas of land and/or coastal environments wherein people are an integral component of the system. Together, they constitute a worldwide network linked by International understanding for exchange of scientific information.

The major source of Nitrous oxide and Sulphur Oxide pollution are power plants, Fossil fuel burning, Lightning, Industrial smoke, Chemical and Fertiliser Industries Volcanoes, Seas and Oceans, Decomposition of organic matter and vehicles.

N₂O₃,NO₂ and N₂O₅ are acidic in nature, and when they react with water, they produce acids like HNO₃ (Nitric Acid) and HNO₂ (Nitrous Acid) which causes acid rain.

CO and CO₂ react with rainwater to form weak Carbonic Acid. Thus generally rainwater is naturally slightly acidic.

The first law of thermodynamics is not adequate in predicting the direction of a process. It is the law of conservation of energy. However, it does not predict whether the process will occur spontaneously and if so, in which direction. For example, the first law of thermodynamics does not indicate whether heat can flow from a colder end to a hotter end or not. 

Aryl halides are less reactive towards nucleophilic substitution reaction as compared to alkyl halides due to resonance stabilization. In alkyl halides, the carbon atom is sp³-hybridized whereas, in aryl halides, it is sp²-hybridized and hence, more electronegative.

Here compound A₃(BC₄)₂ is possible as in it sum of oxidation numbers is zero as follows:

3 (+2 ) + 2 × 5 + 8(−2) = 0