Answer: Option D. -> All of these
:
D
The word soil has such a diverse meaning, it could refer to volcanic black soil or iron rich red soil or grainy and golden desert sand or even the wet and nutrient rich topsoil of the rainforest. These differences in soil are dependent on the climate, the weathering process, and whether soil is transported or sedimentary. Another important characteristic is water retention. Various characteristics of soil including soil composition, grain size and the presence of organic matter determine the percolation and water holding capacity of the soil. This is important because the primary source of entry for water into plants is through theroots in the soil. If the soil cannot retain water, then it cannot foster plant growth.

Answer: Option C. -> Haeckel
:
C
Ecology is derived from the Greek word 'oikos', which means home and 'logos' which means study. The termecologyis fairly recent, it was coined by German biologist Ernst Haeckel.

Answer: Option D. -> Sex ratio
:
D
The sex ratio is the ratio of males to females in a population. The human sex ratio is usually represented as the number of females normalized to per thousand males.

Answer: Option C. -> Shorter ears and limbs in mammals living in colder regions
:
C
The rule says that the body shapes and proportions of endothermsvary by climatic temperature by either minimizing exposed surface area to minimize heat loss in cold climates or maximizing exposed surface area to maximize heat loss in hot climates. Thus the rule predicts that endotherms from hot climates usually have ears, tails, limbs, snouts, etc. that are long and thin, whereas equivalent endotherms from cold climates usually have shorter and thicker versions of those body parts.

Answer: Option B. -> Population density
:
B
Population Density can be defined as the number of individuals of a population per unit space. Population size is the number of individuals of a population, and a population itself can be defined as a group of individuals of the same species in a given area. Distribution of a population is the pattern in which a population is distributed in the given space.

Answer: Option B. -> individuals in a species in a given area
:
B
All members or individuals of a particular species living in a particular area constitute its population. It is ahigher level of organization than organisms because it consists of a group of organisms of the same species. Communities, on the other hand, are a group of interacting populations. The ecosystem is a biotic community interacting and functioning with the abiotic or physical factors of an environment.

Answer: Option B. -> False
:
B
The type of soil in an area determines the type of plants growing in that area which in turn, determines the type of animals that live there.

Answer: Option B. -> Epilimnion
:
B
The epilimnion or surface layer is the top-most layer in a thermally stratified waterbody.Hypolimnion is the lower layer or the deeper layer in a thermally stratified waterbody. Thermocline is defined asa transition line in a water body such as a lake, marked by a layer above and below which the water is at different temperatures.

Answer: Option D. -> dNdt=rN(K−NK)
:
D
The correct equation is
$\frac{dN}{dt}=rN\left(\frac{K-N}{K}\right)$
Where r = Growth rate of the population
N = Number of individuals in the population/Population size
t=time
d=conventional mathematical symbol for instantaneous change
K= carrying capacity

Answer: Option A. -> Sandal wood
:
A
Sandalwood is a partial root parasite which photosynthesize their own food, but tap the roots of other species for water and inorganic nutrients.