Question

Fist organs to develop in a human embryo? and when ___ ___ and number of days ____

a) Liver; during the first week; 7 days
b) Heart; during the second week; 14 days
c) Lungs; during the third week; 21 days
d) Kidneys; during the fourth week; 28 days

Answer 1

The first organ to develop in a human embryo is the heart, which starts beating and pumping blood around day 21 or 22, just three weeks after fertilization.

Step-by-step explanation:

The heart is the first functional organ to develop in the human embryo. It begins beating and pumping blood around day 21 or 22, a mere three weeks after fertilization.

The early development of the heart is reflected by the prominent heart bulge that appears on the anterior surface of the embryo.

By the end of the third week, the heart is already functioning and continues to develop for several more weeks.