What would make humans faster, according to Alexander, is if we had legs
like an ostrich. Ostriches run on their toes, with their ankles 'a good
bit of the way up the leg', and carry almost all their leg muscle on
short thighbones at the very top. They can run up to 69 kilometres an
hour (kph). Human feet are also a drawback. Unlike ostriches which have
smallish feet but manage to keep their balance by spreading their wings
as they run, humans have evolved big, floppy feet to keep them upright.
What we gain in power and balance from the oversized appendages is more
than lost in the added weight and awkwardness they cause.
1. Which **TWO** characteristics of an ostrich play a part in their success as runners?
请选择 2 个答案