Vascular plants and air-breathing animals first appeared during the:a
Silurian period.
b. Ordovician period.
c. Cambrian period.
d. Permian period.
e. Cretaceous period.
A
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The smooth endoplasmic reticulum has ribosomes attached to it
Indicate whether the statement is true or false
Donating blood in the United States
A) requires that the donor be at least age 17. B) does not involve a physical examination. C) though beneficial, may take several hours to complete. D) depends on donors with no prior sexual history. E) is easy and painless, and many donors are allowed to give 5 to 10 units at a time.
A student observes a researcher streaking a plate numerous times, flaming the loop between streaks. The researcher is likely using the ______ method to isolate microorganisms.
Fill in the blank(s) with the appropriate word(s).
The upper chamber on each side of the heart is the ventricle.
a. true b. false