Signals from the atrioventricular (AV) node are carried to the bottom of the heart by ____
a. the sinoatrial (SV) node
b. Purkinje fibers
c. pacemaker cells
d. neurogenic cells
e. the polarization node
ANSWER: b
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An ecosystem includes both the living organisms and abiotic materials that function together
Indicate whether the statement is true or false.
Why would it be more difficult to treat diseases in humans caused by members of the Eukarya than diseases caused by the Bacteria?
A. Multicellular organisms always have their own immune systems to contend with-so any treatment we develop needs to overcome this built-in protection mechanism in such organisms. B. Since bacteria are so much simpler (being single-celled), they are inherently easier to kill off than multi-cellular eukaryotic microbes. C. Eukaryotic microbes use many of the same enzymes and systems as humans-so we lose the ability to target certain molecules that might be present ONLY in the cell type we want to eliminate. There's too much overlap when both organisms are eukaryotic. D. Eukaryotic microbes (unlike prokaryotes) often secrete compounds that breakdown and eliminate drugs used against them. This makes them much harder to effectively eliminate than bacteria.
Which bird is a brood parasite and lays its eggs in the nests of other birds?
A. Catbird B. Cowbird C. Magpie D. Kirtland warbler E. Blue jay
Is the following statement true or false? Explain
Somatic cells leave no progeny and thus, in an evolutionary sense, exist only to help create, sustain, and propagate the germ cells. What will be an ideal response?