Which of the following is not a beta-lactam antibiotic?
methicillin
vancomycin
cephalothin
penicillin g

vancomycin

Explanation:

β-lactam antibiotics are those antibiotic that that contain a beta-lactam ring (the cyclic amide with the nitrogen atom attached to the β-carbon) in their molecular structures. This class of antibiotics is the most commonly used and it includes penicillin derivatives, cephalosporins, monobactams, and carbapenems. The mechanism of action of β-lactam antibiotics is inhibition of cell wall biosynthesis in the bacteria.

tsd is temerature dependent sex determination.

tsd: it is a type of environmental sex determination in which the temperature experienced during embryonic/ larval development (ambient temperature for development) determine the sex of the offspring.

crocodile displays the tsd where the ambient temperature of the developing egg determines the individual's sex. for example in the american alligator's eggs, incubation at 33 ºc produces mostly males, while incubation at 30 ºc produces mostly females. so if the american alligator's egg will get the ambient temperature (33 degree celcius)during embryonic development from egg, the offspring will be male and same for the female sex determination.

sodium i think the chemical element of atomic number 11, a soft silver-white reactive metal of the alkali metal group.