Lichens have been described as "dual organisms<span>" because they are symbiotic associations between two (or sometimes more) entirely different types of microorganism - a fungus (termed the mycobiont) a green alga or a cyanobacterium (termed the photobiont).
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An independent variable is a variable which change is not affected by that of another variable. By process of elimination you can take out B and C. An independent variable can also change so that takes out A. That leaves D.
Answer:
ER → ER-to-Golgi transport vesicles → Golgi cisternae → secretory or transport vesicles →cell surface (exocytosis) (see Figure 17-13). Small transport vesicles bud off from the ER and fuse to form the cis-Golgi reticulum.