A first-hand source such as an experiment is called a primary source.
A primary source is where you can share new information or report on what you have discovered. Some primary sources are research data, interviews, audio recordings, and autobiographies.
A secondary source is where you describe and discuss about the primary sources. They are used to collect and gather primary source information. Some secondary sources are textbooks, review articles, and scholarly books.
A tertiary source is a source about summaries. A tertiary source can be used to look up information or get an overview about what it is you are wanting to know. Some tertiary sources are dictionaries, handbooks, encyclopedias, Wikipedia, and guidebooks.
Connell's famous barnacle experiment was initiated to learn more about competitive exclusion and distribution of branacle species. Barnacle species are distributed in distinct zones on the rocky shores of the Atlantic coast. The Chthamalus in upper intertidal zone; is a smaller species and the semibalanus in low intertidal zone which is a larger species. Chthamalus found in the higher physical stress and higher temperatures because the low tide levels causes them to be exposed to the extreme outside environment for longer periods of time than the semibalanus. Additionally barnacles can only feed while submerged and the higher up shore a barnacle is, the less it can feed and grow. The experiment wanted to understand why they lived this way.
I believe the answer is d<span>eciduous </span><span>trees.</span>