What does el muslo mean?

they need to keep water moving over their gills so they seem to have active periods and restful periods instead of undergoing deep  sleep.  they sleep swim

explanation:

the right answer is c. tiempos

el partido de fútbol tiene dos tiempos

in english, this translates:

a football match has two halves

these halves cosists of 45 minutes each.   each half runs continuously. on the other hand, there is usually a 15-minute half-time break between halves.