You can choose from in-person surveys (one-on-one interviews carried out at high-traffic locations), telephone surveys (less expensive than one-to-one interviews), mail surveys (easy to reach a large audience) and online surveys (simple and inexpensive way to collect data, though not reliable).
A binary tree of depth d is an almost complete binary tree if: 1  Each leaf in the tree is either at level d or at level d â 1. 2  For any node nd in the tree with a right descendant at level d, all the left descendants of nd that are leaves are also at level d.
A leaf is an above-ground plant organ. Its main functions are photosynthesis and gas exchange. A leaf is often flat, so it absorbs the most light, and thin, so that the sunlight can get to the chloroplasts in the cells. Most leaves have stomata, which open and close. They regulate carbon dioxide, oxygen, and water vapour exchange with the atmosphere. Plants with leaves all year round are evergreens, and those that shed their leaves are deciduous. Deciduous trees and shrubs generally lose their leaves in autumn.