Final answer:
Prior to his journey on the HMS Beagle, Charles Darwin believed that species remained unchanged since creation, a common view of his era. The correct option is a. Species remained unchanged since the time of creation.
Step-by-step explanation:
Before he sailed on the HMS Beagle, Charles Darwin's beliefs about species were largely in line with the conventional thinking of his time. This included the idea that species remained unchanged since the time of their creation. The prevalent belief during Darwin's early life was that all species were created at the same time and remained unchanged thereafter. However, Darwin's observations and studies during his five-year voyage led him to conceive his theory of evolution by natural selection, which was a revolutionary departure from the static view of species.