(A) The variations in the physical and chemical conditions of different habitats are primarily determined by two major factors:
$(a)$ Abiotic factors: These include Temperature,Water,Light,and Soil. These non-living components significantly influence the environment of a habitat.
$(b)$ Biotic factors: These include pathogens,parasites,predators,and competitors with which an organism interacts constantly.
Key Abiotic Factors:
$1$. Temperature: It is the most ecologically relevant environmental factor. It affects enzyme kinetics,basal metabolism,and physiological functions. Organisms are classified as Eurythermal (wide range) or Stenothermal (narrow range).
$2$. Water: It is essential for life. Productivity and distribution of plants depend on water. For aquatic organisms,water quality ($pH$ and salinity) is crucial. Organisms are classified as Euryhaline (wide range of salinity) or Stenohaline (narrow range of salinity).
$3$. Light: Essential for photosynthesis in autotrophs. Many plants are adapted to low light conditions. Light also acts as a cue for animals for foraging,reproduction,and migration based on photoperiods. Spectral quality is also vital,as $UV$ components can be harmful.
$4$. Soil: The nature and properties of soil (composition,grain size,percolation,water-holding capacity) determine the vegetation and,consequently,the animal life in a habitat.