A group of tissues that work together to perform a similar function.
A. Cell
B. Organelle
C. Molecule
D. Organ
D. Organ
The correct answer is D. Organ.
To understand why the correct answer is 'Organ,' let's break down the other options:
A. Cell: A cell is the basic structural and functional unit of all living organisms. While groups of cells can come together to form tissues, a single cell alone does not fulfill the definition of a group of tissues working together to perform a similar function.
B. Organelle: This option refers to specialized structures within a cell that carry out specific functions. Similar to a single cell, organelles do not meet the criteria of a group of tissues working together.
C. Molecule: A molecule is a stable assembly of two or more atoms bonded together. It is even further removed from the concept of a group of tissues working together.
Therefore, the correct answer is D. Organ. An organ is defined as a structure made up of different tissues that work together to perform a specific function within an organism. Examples of organs include the heart, lungs, liver, and kidneys.