In what way are monotremes similar to more ancestral chordate lineages, as opposed to more recently evolved mammals?
A) Monotremes lay eggs; other mammals bear live young.
B) Monotremes perform little parental care; other mammals use lactation to feed offspring.
C) Monotremes do not have jaws; other mammals do.
D) Monotremes are ectothermic; other mammals are endothermic.
E) Monotremes perform external fertilization; other mammals perform internal fertilization.

Question

Quizplus · Accepted Answer

Monotremes, like more ancestral chordate lineages, lay eggs, whereas other mammals have evolved to bear live young. This is a key difference between monotremes and more recently evolved mammals such as placental and marsupial mammals.

In What Way Are Monotremes Similar to More Ancestral Chordate