Species is the basic unit in a biological classification and taxonomic ranking system. Generally, species is defined as a group of organisms in which two individuals are capable of reproducing their offspring, Organisms belonging to the same species in a particular locality is termed as population. 

According to Darwin, evolution happens through natural selection which is a differential success in reproduction and adaptation of the organisms to their environment. The population is defined as a group of interbreeding organisms belonging to a particular species and sharing a common geographic area. Thus the smallest unit that can evolve through natural selection is the population. Thus, the correct answer is option D.

The term population refers to the number of animals or people in a particular place. The term also includes  group of similar organisms living in the same region or habitat such as organisms of the same species or number of honeybees in an orchard in one spring.

Stationary phase (zero growth or plateau rate) of population occurs when birth and death rates are equal, the population stabilizes around the carrying capacity of the environment.

Population Dynamics is a branch of science. It deals with and studies the age, and size of a population. It also studies the other components of a population. As a result, it studies the over all nature of the population.

The answer is population because, population is defined as a community that consists of all the individuals of a given species in a specific area. All animals and plants of an area defines all species of plants or animals and in that sense we can say that number of plants or animals in the given area is there. But for a population to form we take into account all the individuals of a given species only, it makes it specific and therefore cannot comprise of  all the animals or plants. So the correct answer is ' all Individuals of a species'. 

The sequence proposed by Darwin and Wallace for organic evolution is Overproduction, variations, constancy of population size, natural selection.First the species produces enormous number of offspring which contains variation. Then extra population is eliminated because not all the offspring can survive because of population stress. Lastly the natural selection operates for the survival of the fittest.

Bagasse is the residue of sugar cane  after the sugar cane containing the  juice is crushed and squeezed. Bagasse around 40%-50% of total sugar cane. 

The diverse climate and the seasonal variations lead to the formation of several zones having flora and fauna with the phenotypic difference. An ecocline or simply cline describes an ecotone in which a series of biocommunities display a continuous gradient. The term was coined by the Huxley in 1938. Clines are the source of genetic and phenotypic variations. It consists of different forms of species, that exhibit gradual phenotypic and / or genetic differences over a geographical area, typically as a result of  diverse environmental condition. 

The differential success in the reproduction of individual organisms is a natural selection that takes place due to the interactions between individual organisms and their environments. Studies however, show that individual organisms do not evolve but it is the population that evolves. Hence, the correct answer is option D.

If the resources are unlimited, the population can continue growing exponentially. In the first year, there were 4 rabbits. In the second year, there were approximately 4 × 4 (4²), or 16 rabbits. In the third year, there were 4 × 4 × 4 (4³) rabbits, about 64. In the fourth year, there were approximately 4 × 4 × 4 × 4 (4⁴) rabbits, or about 256. Following this pattern, we can assume in the fifth year there would be approximately 4 × 4 × 4 × 4 × 4 (4⁵), or 1024 rabbits which is approximate 1000. 

A population is a group of individual of a species inhabiting a particular geographic area. Number of individuals (population size), sex ratio (ratio of total individuals of two genders), age distribution (number of individuals in different age groups namely, childhood, adults and old age) and death rate (ratio of number of dying individuals to total population size) are some of the characters of population. The phenotype is visual/physical expression of the genotype of an individual; hence, it is characters of individually determined by its genotype. Thus, the correct answer is option B.

The phenotype is not the characteristic of the population. It is the set of observable characteristics of an individual resulting from the interaction of its genotype with the environment

Population is a group of individuals of same species that occupy a specific area. A species can have one or more than one population i.e. population is local subset of species and a species can have many populations inhabiting in different areas. Since many populations that can interbreed make a species, these terms are not interchangeable.  Thus, the correct answer is option C.

Demographic transition of a society is the changing pattern of the population from high birth and death rates to the low birth and death rates over the time period. It indicates the economic changes in the particular region as the country develops from a pre-industrial to an industrialized one. Thus, the correct answer is option A.

First population count in India was done in 1872 but due to many irregularities in it, 1891 census is considered as country's first census.

Species is a group of the same kind of the organisms.

Population dynamics is a study of population. it includes size and age of a population, and also its composition. It considers these as dynamic systems. It also studies the biological environment affecting these dynamics.

"Population" is defined as a group of individuals of the same species living and interbreeding within a same given area. Members of a population often rely on the same resources and are subject to similar environmental constraints.

Malthus termed population as "Self perpetuating unit" in his book, "An Essay on the Principle of Population," which was published in 1798.

A population is all the organisms that belongs to the same group or species and lives in a particular geographical area with the capability of interbreeding.

A group of different organisms with related characters of a same area is called population.

 A population is a group of individuals belonging to a species occupying a given area at a particular time

Population ecology is the sub field of ecology that deals with the dynamics of species populations and how these populations interact with the environment. It is an important area because it links the ecology to population genetics and responsible for evolution. 

The principle of competitive exclusion is also called as Gause's Competitive Exclusion principle which states that two closely related species competing for the same resource can not co-exist indefinitely and the competitively inferior one will be eliminated eventually and this was given by G.F. Gause. So the correct option is "G.F. Gause"

A population may be defined as a group of individuals belonging to a single species. The units of study are populations. Study of interaction between individuals in terms of growth, reproduction, dispersal etc., constitutes population ecology. 

In modern civilised world, the greatest predator of man is man. Man indulges itself in the activities like deforestation which creates disbalance in nature and generates threats. The population explosion, global warming and floods are the other natural process which disturbs the equilibrium.

If the nutrients and other resources are limited they will limit the population size and it will reach the "carrying capacity" of the environment and rabbits will compete with one another (intraspecific competition) for these limited nutrients. Therefore, the correct answer is option E.

The population is individuals of same species that occupy a specific area. The ecosystem is an assemblage of different species of an area and abiotic factors of a geographical area and also takes account of the interaction between them. The part of the earth where life exists is referred to as biosphere. A group of organisms that share similar ecological niches in different areas constitute species. The community is a group of populations of different species living together in a habitat and interacting with each other. Thus, the correct answer is B.

Due to beetle infestation, 80% of the trees on the west side of the range were killed. This will result in the alteration of allele frequencies. Certain alleles are lost during infestation. In the small population of the west side, genetic diversity is less compared to that of a large population in the east. Due to less genetic diversity, phenotypic variations will also be lower on the west side. Hence, the two side of populations will be less genetically similar than the earlier. 

Evolution takes place due to various reasons like natural selection, mutation, genetic drift. Phenotypic variations must be based on genetic variations rather than on varying environmental conditions. Sexual reproduction results in the genetic variation but does not affect the natural selection. Also, limited food resources may drive natural selection but is not the reason for natural selection to occur.

A population is all the organisms of the same group or species, which live in a particular geographical area, and have the capability of interbreeding. They are capable of interbreeding or reproduction.