Please help and, please don't take this is me being ride but, ONLY ANSWER IF YOU PLAN ON ANSWER THE 2 QUESTIONS please and thank you
have a great day/night or evening sr or ma'am

1) a and c

2)b and c

Explanation:

1) the first and last box because gravitational pulls depend on the distance and size of and object to another object. If the objects are farther from eachother, than the gravitational pull decreases. Also if an object has a bigger size its gravitational pull increases.

2) b and c because it even says the spend probes are used to collect info, and it is less to use them instead of humans. Also we dont know for sure if the trip will kill us humans and we also dont know if the distance is to far to survive because that has never been proven.

he made 11 calls in one day