These unsegmented worms have a full digestive system even when parasitic.
Answer:
Chromosomes were first named by cytologists viewing dividing cells through a microscope. The modern definition of a chromosome now includes the function of heredity and the chemical composition. A chromosome is a DNA molecule that carries all or part of the hereditary information of an organism. In eukaryotic cells, the DNA is packaged with proteins in the nucleus, and varies in structure and appearance at different parts of the cell cycle.
Explanation:
Cells reproduce genetically identical copies of themselves by cycles of cell growth and division. The cell cycle diagram on the left shows that a cell division cycle consists of 4 stages:
G1 is the period after cell division, and before the start of DNA replication. Cells grow and monitor their environment to determine whether they should initiate another round of cell division.
S is the period of DNA synthesis, where cells replicate their chromosomes.
G2 is the period between the end of DNA replication and the start of cell division. Cells check to make sure DNA replication has successfully completed, and make any necessary repairs.
M is the actual period of cell division, consisting of prophase, metaphase, anaphase, telophase, and cytokinesis.
Cellular respiration, on the other hand, is the process by which living things convert oxygen and glucose to carbon dioxide and water, thereby yielding energy. It does not require the presence of sunlight and is always occurring in living organisms. Cellular respiration takes place in the mitochondria of cells.
The process of when a lake freezes in the winter and thaws in the spring without changing the size or shape is neither constructive or destructive! It's neither.
