What does the forward arrow in a chemical equation mean

When elements that form a mineral dissolve in hot water, they form a mixture called a(n) a)geode b)vein c)evaporation d)crystallization e)magma f)lava g)solution h)gem

Explain how the number of similarities between the embryos from early stage to late stage is used as evidence of a common ancestry

Which type of respiration takes place when there is no oxygen present