When a nervous stem cell differentiates into a neuron versus a neuroglial cell.

When the high level of a substance decreases the production and secretion of a hormone.

When an injury activates a few platelets that lead to the activation of thousands of plasma fibrinogen until a blood clot is formed.

When the cardiovascular, respiratory, urinary, nervous and endocrine systems coordinate to maintain blood pH between 7.35 and 7.45.

When the body attenuates sudden significant changes so that most indicators fluctuate within a narrow range around a set value.

When an organism has a particular characteristic that makes them better suited for a particular function.

When changes in an organism accumulate over generations such that they become better suited to their environment.

When changes in behavior are prompted by an event in the organism’s environment.

Une courbe reliant toutes les positions qu'une particule fluide donnée prends le long de l'écoulement.

Une courbe qui est tangente en tous points au vecteur vitesse.

Une courbe reliant toutes les particules fluides qui sont passées par un même point en amont.

Une courbe sur laquelle le module de la vitesse a toujours la même valeur.