Question
This structure develops into the urachus (“YOO-ruh-cuss”) during fetal development. For 10 points each:
[10h] Name this extraembryonic membrane found in amniotes, which facilitates gas exchange and handles liquid waste. This membrane fuses with the chorion (“KOR-ree-on”) into a namesake placenta in mammals.
ANSWER: allantois (“uh-LAN-toh-iss”) [accept chorioallantoic membrane]
[10e] The allantois also forms an axis for the development of this other structure along with the yolk sac. This structure is rich in Wharton’s jelly and connects the fetus to the placenta.
ANSWER: umbilical cord
[10m] The allantois appears mid-gastrulation before the formation of these structures in humans, but after they form in pigs and rabbits. These paired blocks of paraxial mesoderm eventually give rise to the musculoskeletal system.
ANSWER: somites (“so-mights”)
<Biology>
Summary
| 2025 ACF Nationals | 04/19/2025 | Y | 11 | 12.73 | 100% | 18% | 9% |
Data
| Columbia A | Chicago A | 10 | 10 | 0 | 20 |
| Toronto C | Chicago B | 0 | 10 | 0 | 10 |
| NYU | Illinois A | 0 | 10 | 0 | 10 |
| Johns Hopkins | Stanford | 0 | 10 | 10 | 20 |
| Northwestern | Georgia State | 0 | 10 | 10 | 20 |
| Virginia Tech | Ohio State | 0 | 10 | 0 | 10 |
| Toronto B | Michigan | 0 | 10 | 0 | 10 |
| UC Berkeley B | UCF | 0 | 10 | 0 | 10 |
| Florida | WUSTL A | 0 | 10 | 0 | 10 |
| British Columbia | WUSTL B | 0 | 10 | 0 | 10 |
| Vanderbilt | Waterloo A | 0 | 10 | 0 | 10 |