Which of the following is a feature of Equus?
(a) Three digits with hoof on each forelimb and hindlimb
(b) Four digits with hoof on each forelimb and two digits with hoof on each hindlimb
(c) Two digits with hoof on each forelimb and hindlimb
(d) One digit with hoof on each forelimb and hindlimb
(d) One digit with hoof on each forelimb and hindlimb.
Explanation:
The evolution of the modern horse (Equus) saw progressive reduction in the number of digits. The earliest ancestors had multiple digits, but through evolutionary adaptation for speedy running, the present-day Equus possesses only one functional digit, each with a single hoof, on all four limbs. The other digits exist as splint bones and are vestigial.
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