Some of the challenges are the unpredictable fish and the risk of scratching againest coral or drowning for not focusing on your oxygen tank.
Answer:
A star with 15 solar masses is too big to be a main-sequence star.
Always wear protected face gear and body gear, make sure you have an adult present and a fire extinguisher
Answer: 1.2 m/s
Explanation:
Velocity 
is defined as the variation of position of an object or body in time. So, if we know the distance the seed traveled and the time, we can calculate its velocity:
Where:
is the distance the maple seed traveled
is the time
Then:
This is the seed's velocity
