It affects your lungs the most.
Muscular strength
in case you didn't know the definition of muscular strength, you could use process of elimination. it's not muscular endurance because endurance is testing how long you can do something over a period of time, and the question is asking about all at once. it's not flexibility or body composition because neither are testing how much force your body can exert. that leaves muscular strength.
Each child has a 25% chance of having brown eyes and a 75% chance of having blue eyes. This is simplified since the other eye color genes (like those that influence green eyes) are being ignored. But it does mean that brown (or green or hazel or…) eyes are a definite possibility for these blue eyed parents