What moves in one direction through an ecosystem rather than being used over and over again like nutrients are?​

I believe its energy - if im incorrect my apologiesss

The correct is the answer is option D.

Explanation:

Non-specific defense response is the immune system that provides defense against more than one type of antigen or pathogen. The non-specific defense provides responses include physical barriers, protein defenses, cellular defenses, inflammation, and fever. Mucus in respiratory tracts and nose traps microbes and pathogens from invading the body.  

Wax also captured foreign bodies and other pathogens from entering our ears. Non-specific defenses are surface coverage defenses.  

T-cells are the specific white cells that target specific antigens or pathogens that are a specific defense provided by the specific immune system.

Thus, the correct answer is option D.