Which are electrical "nodes" of the heart? Check all that apply.

sinoatrial node

aortic node

lymph node

heart node

atrioventricular node

What are some aquatic organisms that live in cold water temperatures?

Aparent with freckles is crossed with a parent without freckles. the punnett square shows the possible genotypes and phenotypes of the offspring. which statement accurately describes the probability of phenotypes? a.the offspring are more likely to have freckles. b.the offspring are more likely to have no freckles. c.the likelihood of the offspring having freckles and not having freckles is the same. d.the likelihood of the offspring having freckles and not having freckles cannot be determined.

According to theories of how life began, how did early organic molecules begin to separate from the outside world? a: specialized enzymes were required b: chains of amino acids created a barrier c: formation of microspheres or vesicles d: rna catalyzed the formation of membranes