Question

how do strong core muscles help a person run faster?
they improve the bodys center of balance and allow more power from the legs
they reduce the chance of injury
they make the runner lighter

Explanation:

Strong core muscles improve the body's center of balance and allow more power from the legs. This is because the core muscles act as a stable base. When the core is strong, it can transfer power more efficiently from the legs to the rest of the body during running. Making the runner lighter is not a function of core muscles. While strong core muscles can contribute to better form and potentially reduce the risk of injury indirectly (by maintaining proper alignment), the most direct way they help with running faster is through improving balance and power transfer.

Answer:

They improve the body's center of balance and allow more power from the legs.