How does a hydrogen bond form?

Which of the following is most important in making the typical seed more resistant to adverse conditions than the typical spore? a) a different type of sporopollenin b) an internal reservoir of liquid water c) integument(s) d) ability to be dispersed e) waxy cuticle

Archaebacteria use for movement. celia flagella pili cell walls

Ascientific idea becomes valid when it is what?