Multiple choice

Mammary glands without teats are present in

  1. theria

  2. utheria

  3. metatheria

  4. prototheria
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Prototherians (monotremes like platypus and echidna) have mammary glands that lack nipples. Milk is secreted onto specialized skin patches and the young lap it up. Theria includes all live-bearing mammals, Eutheria are placental mammals (with nipples), and Metatheria are marsupials (also have nipples). Option B has a typo ('utheria' should be 'eutheria').

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