Suppose One Twin Takes a Ride in a Spaceship Traveling

question 51

Multiple Choice

Suppose one twin takes a ride in a spaceship traveling at a very high speed to a distant star and then back again,while the other twin remains on Earth.Compared to the twin who remained on Earth,the astronaut twin is

• A)younger than the Earth-twin.
• B)the same age as the Earth-twin.
• C)older than the Earth-twin.
• D)The ages cannot be determined from the information provided.

---

Definitions:

Anterior-Posterior Axis

A directional axis in biology, referring to the front (anterior) and back (posterior) orientation of an organism or its parts.

Ray-Finned Fishes

A class (Actinopterygii) of modern bony fishes; contains about 95% of living fish species.

Tetrapods

A vertebrate group that includes all species with four limbs, such as amphibians, reptiles, birds, and mammals, including those that have lost limbs through evolution.

Eutherian Mammal

A type of mammal characterized by complex placental development, giving birth to live young at a relatively developed stage.