Limits are the outer boundaries of a group in regard to behaviors that will be accepted within the group.
Answer:
At the start of the war the land and sea forces used the aircraft put at their disposal primarily for reconnaissance, and air fighting began as the exchange of shots from small arms between enemy airmen meeting one another in the course of reconnoitering. Fighter aircraft armed with machine guns, however, made their appearance in 1915. Tactical bombing and the bombing of enemy air bases were also gradually introduced at this time. Contact patrolling, with aircraft giving immediate support to infantry, was developed in 1916.
Explanation:
B. Separate themselves from those who were unlike them.
In most cases, the engineered works will have a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as slack water levels, often just called levels.