In the summer, the arctic fox appears brown
because its cells produce a dark pigment.
however, in the winter, the arctic fox appears
white because the dark pigment is not produced.
the color change is most likely due to the effect of
(1) different genes produced in the different
seasons
(2) increased pollution on genetic mutations
(3) environmental conditions on gene expression
(4) poor nutrition on cell growth and development

Vegetation that grows along the floors of tropical and temperate forests is called undergrowth. how is the undergrowth of a tropical rain forest most likely to differ from the undergrowth of a temperate forest? a. a tropical rain forest's undergrowth most likely experiences periods of dormancy during colder weather. b. a tropical rain forest's undergrowth most likely experiences periods of dormancy during rainy weather. c. the undergrowth of a tropical rain forest most likely requires less sunlight. d. the undergrowth of a tropical rain forest most likely requires more sunlight.

Is there any species that went extinct in recent years due to natural causes (not caused by human interaction). if so, what caused it?

Fredrick griffith made a scientific discovery in 1928