What are the two chemicals that go back and fourth in the oxygen cycle

How does land development destroy ecosystems? it increases human carrying capacity too rapidly. it converts them into residential or agricultural areas. it forces humans to import non-native plants and animals. it expands the natural range of native wildlife species.

According to the big bang theory, after the "bang," the universe remained dark until about  300,000 yearsone billion yearsthree minutesthree billion years  later, when neutral atoms began to form.

Afamily has a y-linked disease that affects the father. what is the chance of a male offspring inheriting the same disease? oa. 100% ob. 50% oc. 25% d. 0%