Final answer:
If Martian life resembles Earth's, its macromolecules will be based on carbon, essential for forming proteins, nucleic acids, and other organic molecules necessary for life.
Step-by-step explanation:
If life on Mars is fundamentally like life on Earth, its macromolecules will be based on the element carbon.
Carbon's ability to form four covalent bonds makes it uniquely suited to be the backbone for organic molecules, such as proteins, nucleic acids, carbohydrates, and lipids, which are necessary for life.
These organic molecules are crucial for the structure and function of life's cellular machinery.
Since the chemical evolution of the universe has produced the elements required for life, and given that Mars had similar surface conditions to Earth approximately 4 billion years ago, it is plausible that Martian life, if it exists, would share this carbon-based molecular structure.
By following the water on Mars, scientists hope to uncover evidence of life because liquid water is another requirement shared by all life on Earth.