À l'aide des notions de force et de pression, explique comment fonctionne une pompe de vélo.

Embryos of different species look very similar, which shows that the organisms share a ancestor.

Provide a stepwise curved arrow mechanism that fully explains the outcome of the reaction shown below. oh нао* heat он

Why is the bond angle in a water molecule less than the bond angle of methane? a. the central oxygen atom in water has two lone pairs of electrons, whereas the central carbon atom in methane has no lone pairs. b. the central hydrogen atom in water has one lone pair of electrons, whereas the central carbon atom in methane has two lone pairs. c. the central oxygen atom in water has four lone pairs of electrons, whereas the central carbon atom in methane has only one lone pair. d. the central oxygen atom exerts more repulsive force on surrounding atoms than the central carbon atom in methane does. reset next