The n nodes in a binary tree can be visited in:

\Theta(n) time
  • \Theta(1) time
  • \Theta(\log n) time
  • \Theta(n) time
  • \Theta(n \log n) time
  • \Theta(n^2) time

This would be done by a traversal. How much work does a traversal do at each node?

Each node is visted once, with constant time spent at each.