Answer:
B. an asteroid belt lies between them.
Explanation:
The asteroid belt is the circumstellar disc in the Solar System located roughly between the orbits of the planets Mars and Jupiter. It is occupied by numerous irregularly shaped bodies called asteroids or minor planets.
Answer:
D. Fossil record.
Explanation:
The fossil record evidences the evolutionary history of life on Earth by tracing the life forms that existed from earlier geological times and remained in the sedimentary rock. Different fossils were dated in the sedimentary rocks of all geological periods. The simplest forms of life were discovered in the oldest rocks, while more complex fossil organisms were found in the newest rocks. In consequence, the fossil record can support the evolutionary process as proposed by Charles Darwin, who indicated that the simplest forms of life evolved in more complex organisms.
The correct answer is signal transduction.
Signal transduction also called cell signaling refers to the conduction of molecular signals from the external of the cell to its internal. The signals perceived by the cells must be conducted efficiently into the cell to make sure an effective response. This step is stimulated by cell-surface receptors.
There are three phases in the procedure of communication or cell signaling, that is, reception, transduction, and response.
