A model organism is a species that researchers study to better understand certain biological processes. Mollusks and arthropods are commonly used as model organisms for studying mechanisms of learning and memory, while sponges and jellyfish are not, Why is this?
A.
Mollusks and arthropods can detect stimuli from their environment, while jellyfish and sponges cannot.
B. Mollusks and arthropods exhibit cephalization, while jellyfish and sponges do not.
Mollusks and arthropods exhibit segmentatic while jellyfish and sponges do not.
Mollusks and arthropods can respond to changes in their environment, whie jellyfish and sponges cannot.

Penicillin is hydrolyzed and thereby rendered inactive by penicillinase (also known as β-lactamase), an enzyme present in some resistant bacteria. the mass of this enzyme in staphylococcus aureus is 29.6 kd. the amount of penicillin hydrolyzed in 1 minute in a 10-ml solution containing 10-9 g of purified penicillinase was measured as a function of the concentration of penicillin. assume that the concentration of penicillin does not change appreciably during the assay. penicillin(μm) amount hydrolyzed(nmol) 1 0.11 3 0.25 5 0.34 10 0.45 30 0.58 50 0.61 (a) plot v0 versus [s] and 1/v0 versus 1/[s] for these data. does penicillinase appear to obey michaelis-menten kinetics? if so, what is the value of km? (b) what is the value of vmax? (c) what is the turnover number of penicillinase under these experimental conditions? assume one active site per enzyme molecule.