Which condition is the temporary absence of spontaneous respiration? a. sleep apnea b. apnea c. respiratory failure d. eupnea?

The condition is B) apnea.

Apnea is a term used to depict the sudden ceasing of immediate respiration. Childish apnea happens in kids younger than one year. Apnea may happen in view of neurological hindrance of the respiratory mood or block of wind stream through the air entries.  

The manifestations of juvenile apnea incorporate the stoppage of breathing during rest, a strange pale blue staining on the skin (cyanosis) and in some cases a curiously moderate heartbeat (bradycardia). Juvenile apnea might be identified with certain instances of unexpected newborn child passing disorder.

the sugar-phosphate backbone forms the structural framework of nucleic acids, including dna and rna. this backbone is composed of alternating sugar and phosphate groups, and defines directionality of the molecule.

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d