What is a spontaneous change in a gene or a chromosome

Characteristic expected of mineral from lava at earth's surface

phaneritic textures in which phaner means visible so phaneritic textures are standard of impertinent volcanic rocks. these rocks crystallized gradually under the surface of earth. when the magma cools deliberately then the ores have chance to develop and produce long crystals.

The answer would be c, white eyes are homozygous recessive. in the early 1900s, morgan conducted several experiments with vinegar  flies (drosophila). one  sample revealed an anomaly: a  white-eyed, single male fly. he attempted to breed this fly with the typical red-eyed females. the offspring were all red-eyed. using flies from this new generation (brother-sister pairs)  produced some red-eyed and a few white-eyed flies. the white-eyed were all male. in later experiments, he was able to produce white-eyed females. this proved that white eyes are not lethal to either sex (ruling out a and b). since the percentage of white eyes to red eyes is so low, white eyes are not a dominant trait. it would be a recessive trait. 

Where's the picture of the model?