All of Darwin’s observations would prove this theory true.
Slope
slōp/
noun
1.
a surface of which one end or side is at a higher level than another; a rising or falling surface.
a difference in level or sideways position between the two ends or sides of a thing.
synonyms: gradient, incline, angle, slant, inclination, pitch, decline, ascent, declivity, rise, fall, tilt, tip, downslope, upslope, grade, downgrade, upgrade
"the slope of the roof"
a part of the side of a hill or mountain, especially as a place for skiing.
synonyms: hill, hillside, hillock, bank, sidehill, escarpment, scarp; More
verb
1.
(of a surface or line) be inclined from a horizontal or vertical line; slant up or down.
synonyms: slant, incline, tilt; More
