The correct answer is option Energy is lost at each trophic level.
In a Ecological pyramid, the energy is transferred from the producer to the consumer level. The ecological pyramid is triangular in structure, this is because the number of organism on each successive trophic level is less than the preceding one or the one below it.
The reason of this shape of ecological pyramid is on subsequent trophic level, the amount of energy transferred is only 10%. The rest of the energy is dissipated in the environment in the form of heat. As only 10% of total energy is transferred to the subsequent level, The amount of energy reaching to tertiary consumer is very less that it cannot meet the energy demand of next level.
T cells. When HIV arrives in the lymph nodes – around 24 to 48 hours after exposure – they activate other immune cells, such as CD4 t-cells, HIV's primary target.
When blood is in the lungs,
where oxygen is plentiful, oxygen easily binds to the first subunit and then quickly fills up the remaining ones. Then, as blood circulates through the body, the oxygen level drops while that of carbon dioxide increases. In this environment, hemoglobin releases its bound oxygen.
