Answer:
D. Nucleus.
Step-by-step explanation:
A cell can be defined as the structural, fundamental, biological and functional unit of life. Cells are found in all living organisms because they are the basic unit of life. A unicellular organism refers to a living organism that possess a single-cell while a multicellular organism has many (multiple) cells.
Some examples of cell organelles found in all living organisms such as trees, birds, and bacteria include; nucleus, cytoplasm, cell membrane, golgi apparatus, mitochondria, lysosomes, ribosomes, chromosomes, endoplasmic reticulum, vesicles, etc.
Proteins on the surface of vesicles determine where the vesicles go.
The nucleus is the cell organelle which provides the instructions for these proteins. It controls all the activities taking place in the cell and the synthesis of proteins.