Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems? Energy transfer between trophic levels is usually less than 20 percent efficient. Nutrient cycling rates tend to be limited by decomposition. Many primary and higher-order consumers are opportunistic feeders. Decomposers compete with higher-order consumers for nutrients and energy.

label a cell membrane

label b cytoplasm

label c ribosomes

label d dna

the membrane forms the outside of the cell

cytoplasm is the liquid within

ribosomes are the components within that distribute rna

the dna is the genetic make-up

enzyme active site and substrate specificity

enzymes bind with chemical reactants called substrates. there may be one or more substrates for each type of enzyme, depending on the particular chemical reaction. in some reactions, a single-reactant substrate is broken down into multiple products