Answer:
1.C. Cells, Tissues, Organs, Organ Systems
2.D. Organ Systems, Organs, Tissues, Cells
Explanation:
Cells are the smallest form in the living things organization of structures, then cells form tissues, and tissues form organs, and organs make up for organ systms, so in that order from simplest to most complex the order would be:
Cells-Tissues- organs- Organ systems
And backwards would be
Organ systems-Organs- Tissues- Cells