How are chordates further divided into three subphyla? A. By their habitats
B. By the presence or absence of a notochord
C. By how they obtain food
D. By their body structures

D. By their body structures

Explanation:

They are divided into three subphyla which would be Vertebrate.

the corpus luteum secretes estrogens and progesterone. the latter hormone causes changes in the uterus that make it more suitable for implantation of the fertilized ovum and the nourishment of the embryo. if the egg is not fertilized, the corpus luteum becomes inactive after 10–14 days, and menstruation occurs.

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we need additional information in order to determine the cause of death for anna garcia. there are at least 3 things with explanation included as to why we need them are as follows: