Gross production is the total energy that is acquired at each trophic level. net production is the amount of energy that is left after respiration has taken place. going from one trophic level to the next decreases the energy conversion efficiency, because the net production of each level decreases.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

b is the correct answer

when you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. this increases the space in your chest cavity, into which your lungs expand. the intercostal muscles between your ribs also enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.