Fill in the missing levels of organization in living things from smallest to largest: cell, organ, organism

The correct answer will be option-

1. tissue

2. organ system

Explanation:

The organization of living things shows that life evolved from simplicity to complexity.

A living organism is made up of a cell which is considered the smallest unit of life. The cell gets accumulated and organised to form tissues which perform similar tasks. This tissue further organizes to form organs which specialized to perform coordinated functions. This specialization is known as an organ system and this organ system makes an organism.

Thus, tissue and the organ system is the correct answer.

what are the choices?

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.