1. alginate is
a. reversible hydrocolloid impression material
b. irreversible hydrocolloid impression material
c. polysulfideimpression material
d. polyvinyl siloxane impression material

Option b, Irreversible hydrocolloid impression material

Explanation:

Irreversible is used as an impression material to take impression from edentulous jaws. It is also used in wound healing and drug delivery.

Alginate is a natural polymer found in cell wall of brown seaweed.

Its monomers are β-D-mannuronate and α-L-guluronate.

In association with Ca2+, it forms gel. It is hydrophilic in nature.

answer: the figure is attached herewith.

step-by-step explanation:   we are given to sketch a unit circle and label the terminal points corresponding to

in the attached figure, we have drawn a unit circle, with centre at o(0,0) and radius 1 unit. we have labelled the points a, b, c, d and e corresponding to the angles below

∠aox = 60°,

∠box = 120°,

∠cox = 180°,

∠dox = 240°,

∠eox = 300°.

and the coordinates are a(0.5,1), b(-0.5,1), c(-1,0), d(-0.5,-1) and e(0.5,-1).

thus, the answer is complete.

they are both synthetic elements

explanation:

d