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.
The spread of roots around a plant is usually greater than the depth of the roots is a completely false statement. It totally depends on the type of plant in regards to the type of root it will have. Normally there are two kinds of roots and they are taproot and fibrous roots. In case of taproots the main root goes downwards and smaller roots branches out of it. In case of taproots, it is true that the spread of roots is smaller than the depth of the roots. In case of fibrous roots, the spread of roots is greater than that of the depth of the roots. A wig tree is an example of a plant having taproot. in the wig tree the root can go to a depth of around 120 meters.
At the place marked with the letter A we have a divergent plate boundary. On this type of boundary, the plates are moving away from one another. As they move away, they leave a gap behind them, and the crust is becoming thinner and thinner with lots of cracks in it. Because of that, the high pressures from the mantle manage to push upwards the magma with ease. The magma reaches the seafloor and it is pushing the crust upwards until it breaks it. As the magma pushes the crust upwards,underwater volcanoes are formed, and when the crust is broken by the magma, the magma flows get on the seafloor, cool of very quickly in the water, and create new crust.