Converging lenses are at the center and at the edges. a. thickest, thinnest b. thinnest, thickest

Converging lenses are thickest at the center and thinnest at the edges.

Explanation:

Lenses are transparent medium that refracts all incident light. Converging lens is one of the type of lens that we have and they are also known as convex lenses. Converging lenses are formed from the combination of two convex mirror. They are thickest at the center and thinnest at the edges. All incident light on a convex lens converges after refraction

freezing

deposition

condensation

explanation;

melting also called fusion is the process where solid becomes liquid, sublimation is the process where solid becomes gaseous without first changing to liquid, deposition involves change from gaseous to solid state, freezing involves change from liquid to solid, boiling or evaporation involves change of liquid to gaseous state, while condensation is the change from gaseous state to liquid state.

endothermic reactions involves absorption of heat from the surroundings or the environment while exothermic reactions involves loss of heat energy to the surroundings.

in this case, sublimation, evaporation and melting are endothermic reactions (gain energy from the environment) while, freezing, deposition and condensation are exothermic (loss of energy to the surroundings) reactions.

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