The author says a caisson is kept free of water

because it is like

answer; ///i believe that the correct answer is (c)vetoing executive check first good luck

wood carving remains today the primary sculptural art form of the sub saharan continent. african art history shows the earliest wooden sculptures from the 17th c are attributed to the kuba, central zaire but the earliest surviving sub-saharan sculpture is a zoomorphic head found in 1928 in central angola.

i hope this .