Definition of PLACOID. : of, relating to, or being a scale of dermal origin with an enamel-tipped spine characteristic of the elasmobranchs. ADVERTISEMENT.Greek plak-, plax flat surface.First Known Use: 1842.efinition of PLACOID. : of, relating to, or being a scale of dermal origin with an enamel-tipped spine characteristic of the elasmobranchs. ADVERTISEMENT. Greek plak-, plax flat surface. First Known Use: 1842.
A tree pruner is a class 1 lever. The fulcrum is where the two blades cross, and the load is what you are cutting. The effort is applied to the two handles.
Acer /ËeÉªsÉr/ is a genus of trees or shrubs commonly known as maple. There are approximately 128 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America.Only one species, Acer laurinum, extends to the Southern Hemisphere.cer /ËeÉªsÉr/ is a genus of trees or shrubs commonly known as maple. There are approximately 128 species, most of which are native to Asia, with a number also appearing in Europe, northern Africa, and North America.