Species is the lowest of a population or basic taxonomic category which consists of one or more individuals that resemble one another more closely than individuals of other species.
The members of a species interbreed freely and are reproductively isolated from members of other species. These features make the species basic taxonomic category.

We should call it biodiversity or biological diversity as it shows variety of living organisms present on earth.

Correlated characters are those common features, which are used in delimitation of a taxon above the rank of species.

Largest botanical garden in the world is Royal Botanical Garden, Kew (London).
Some well-known botanical gardens in India are
(i) National Botanical Garden, Lucknow
(ii) Lloyed Botanical Garden, Darjeeling
(iii) Indian Botanical Garden, Sibpur, Kolkata

George Bentham and Joseph Dalton Hooker.

Julian Huxley (1940).

It is because of the great variability in languages in different parts of the word.

Mulus, sterile worker bees

The number and kinds of organisms are never constant at a place, as development and reproduction keep the number changing. This is influenced by season and availability of resources, e.g., number of mosquitoes is very large in warm and humid weather, whereas in extreme summer or winter, they can be seen rarely.

All organisms from the prokaryotes to the most complex eukaryotes can sense and respond to their environment.
The human have five sense organs, which help them to sense their environment.These are eyes, ears, nose, tongue and skin.

The sum total of all chemical reactions occurring in an organism due to specific interactions amongst different types of molecules within the cells, is called metabolism.

In unicellular organisms like Amoeba, bacteria and unicellular algae, reproduction is synchronised with growth, i.e. they reproduce and grow by increase in number of cells.

(i)  Filamentous algae
(ii)  Peritonea of mosses

Living things grow either by increase in cell number or increase in cell mass.

A person lying in coma is not conscious of its surrounding environment. Thus, he/she is not capable of responding to the external environmental stimuli.The person is supported by machines for various functions of the body.The person is otherwise brain dead.Some of these patients never come back to normal life. They can neither be called living nor non-living or dead.

Metabolic reactions can be demonstrated outside the body in cell-free systems. When an isolated metabolic reaction is performed outside the body of an organism in a test tube, it is neither living nor non-living. Hence, while metabolism is a defining feature of all living organisms without exception, isolated metabolic reactions in vitro are not living things, but are living reactions. Here, it can also be said that cellular organisation of the body is the defining feature of life forms.

(i) The taxonomic categories which are always used in hierarchical classification of organisms are called obligate categories.
(ii) The taxonomic categories from species to kingdom are broad categories or obligate categories. However, taxonomists have developed sub-categories in this hierarchy to facilitate more sound and scientific placement of various taxa.
(iii) These are intermediate categories.
(iv) They include subphyla, subclasses, suborders, subfamilies, subgenera, varieties or subspecies.

Each category in taxonomical hierarchy is commonly called taxon.
The different taxonomical categories are-species, genus, family, order, class, phyla/division and kingdom. Some examples of taxa at different hierarchical levels are
(i)  Mangifera indica is a taxon and species is its category.
(ii)  The taxon of all the bacteria is Monera and the category is kingdom.
(iii) The taxon of fishes is Pisces and the category is class.

Now a days, biologists use several principles and criteria to classify the organisms. These are based on morphology, anatomy, cytology, physiology, phylogeny, reproduction, evolution, biochemistry and genetics. Thus, there are several characteristics differences which help in classification. This is the reason of change in classification systems every now and then.

Advantages of scientific names are
(i) These are acceptable in every part of the world.
(ii) These are assigned on agreed principles by scientists.
(iii) These are very specific. It means no two organisms can have the same name.

Biology is the study of story of life on the earth. It is the story of evolution of living organisms on earth. As a student of biology, life can be explained as a unique, complex organisation of molecules expressing itself through chemical reactions, which lead to growth, development, responsiveness, adaptation and reproduction.

The scientist will first identify the family to which the plant belongs
He will further follow the given steps
(i)  Using genus key, the genus is identified.
(ii)  Using species key, identification is carried out
(iii)  As the genus is known, the species is provided now with a latinised name as per guidelines.
(iv)  Type specimen or holotype is placed in a recognised herbarium or museum.
(v) Name, description and report of the discovery is published in a reputed scientific journal.

(i)  Common name: Mustard.
(ii)  Parts of the name: First part represents the genus or generic name, while the second part represents the specific name.
(iii) They are written in Italics in order to highlight their Latin origin.
(iv) Linn written at the end of the name, is the abbreviation of the name of scientist Linnaeus, who gave the name to the plant.