After collecting specimens from many areas of the world, Darwin noted the similarities in them. He discovered that new kinds of species could gradually grow into new ones over years.
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Answer:
D: Nucleus
Explanation:
Prokaryotic cells contain a cell membrane, a cell wall, and cytoplasm. However, they do not have a nucleus. Eukaryotic cells have a nucleus.
Answer: Alexandrium catenella is a species of dinoflagellates. Alexandrium has two flagella that enable it to swim. While one flagellum encircles the cell causing the cell to rotate and move forward, the other extends behind the cell and controls the direction.
The cell wall is composed of cellulose Theca.
Length 20 - 48 μm, width 18 - 34 μm
Yellow-green to orange-brown
Forms chains of 2, 4 or 8 cells