Ecosystem

The word diagram below illustrates a food chain in a forest environment:$ $If the population of predators (wolves) decreases, the herbivore population (elk) is likely to increase since there are fewer predators to keep their numbers in check. This rise in the number of herbivores will lead to more intense browsing of trees (aspen and willow), causing a marked reduction in tree populations. As primary producers, these trees play a crucial role in the ecosystem. If this process continues unchecked, it may destabilize the ecosystem, ultimately leading to its breakdown.

Tropical Rainforest (P): Highest NPP due to favourable conditions like high temperature, moisture, and sunlight.Coastal Zone (S): Moderate NPP, coastal ecosystems like mangroves and estuaries have high productivity, though not as much as tropical rainforests.Tundra (Q): Low NPP due to cold temperatures and short growing seasons.Desert (R): Lowest NPP because of extreme arid conditions and minimal vegetation.

Option A: The movement of energy is unidirectional in the ecological pyramid of energy.This statement isTRUE. Energy flows from lower trophic levels to higher trophic levels, and a significant portion is lost as heat at each transfer. It does not flow back to lower levels. This follows the second law of thermodynamics.Option B: Only of energy is transferred to each of the higher trophic levels in grazing food chain.This statement is generallyTRUE. This is known as the "10% rule" or Lindeman's law of trophic efficiency, an ecological principle stating that on average, only about 10% of the energy from one trophic level is incorporated into the biomass of the next trophic level. The rest is lost as heat during metabolic processes or is not consumed.Option C: All organisms of a trophic level should be included for estimation of energy content of that trophic level.This statement isTRUE. To accurately determine the total energy available at a specific trophic level, one must consider the energy stored inallthe living organisms that constitute that level. Excluding some would lead to an inaccurate estimation.Option D: More than of the solar energy incident on earth is captured by plants and photosynthetic bacteria.This statement isFALSE. Photosynthetic organisms (plants, algae, and photosynthetic bacteria) are remarkably inefficient at capturing solar energy. Typically, only about 1% to 2% (and sometimes up to 5% under optimal conditions for highly productive ecosystems or crops) of theincidentsolar energy that falls on Earth's surface is converted into chemical energy via photosynthesis. A value of "more than 80%" is extremely high and biologically impossible under natural conditions.The final answer is