Answer: b. False
Many mammals rests for a large proportion of the 24 hour. The rest period usually extent during hibernation. The marine mammals tend to rest or sleep with only one hemisphere is kept at rest. It allows them to keep one eye open this allows them to stay alert against the predators. But the terrestrial or land mammals when take rest both the hemispheres of the brain sleep.
On the basis of the above description, most land mammals have the ability to rest one hemisphere of their brains at a time is false.