Make an organized chart of data collected
The answer is competition
During mitosis, the <em />nuclear membrane breaks down and the duplicated chromosomes are separated and evenly distributed to opposite sides of the cell. Cytokinesis involves the division of the cytoplasm and the organelles that are contained within.
This describes the process of cell division. All of these events happen in the M phase of mitosis. The breaking down and fragmentation of the nuclear membrane to expose the genetic material is in the prophase. The next phase is the metaphase when the duplicated chromosomes align in a straight line (metaphase plate). Anaphase involves the separation of chromatids and by the time the chromatids reach the opposite side then the cell enters telophase. Lastly, cytokinesis involves restoration of the nuclear membrane, division of the cytoplasm, and production of two daughter cells.
A scientific theory can always be disproved if someone comes along with better evidence which shows another theory is true. However, most other theories are small improvements on existing ones. Evolution and natural selection (the theory that animals' populations change over time because their environment encourages specific different features for individuals that happen with mutation) was an improvement on the existing "theory" that animals were built to be fit for their environments. The earth rotating around the sun was a theory improving on the idea that the sun and the earth move around so that it looks like the sun moves around the earth. All of these happened because there was evidence, so while theories aren't always absolutely true, many modern theories are typically well-tested and if they aren't, they are usually refered to as hypotheses or models (although models can sometimes also be theories, like the Standard Model)
Well the main purpose of xylem is to transfer sap from the roots to the leaves and phloem typically transports sugars from leaves to sink tissue. Xylem only travels up from the roots but phloem can have either travel up or down. The outside cells of xylem are dead and the the cells that make up phloem are the sieve elements, which are supported by companion cells.
