Which of the following chapters in geologic time occurred before there were abundant animals with hard parts?

A. Paleozoic
B. Mesozoic
C. Precambrian
D. Cenozoic


Answer: C

Environmental & Atmospheric Sciences

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Natural selection can only occur if a heritable trait can be passed on to offspring at a higher rate than other individuals in a population.

Answer the following statement true (T) or false (F)

Environmental & Atmospheric Sciences

What happens to the length of day (the number of hours of daylight) as you move north of the equator?


Figure 9-2: Earth–Sun relations on June solstice.

Noting the orientation of the circle of illumination on June 21, explain the above question.

What will be an ideal response?

Environmental & Atmospheric Sciences

Placer deposits are surface accumulations resulting from the mixing of materials as they are transported

Indicate whether the statement is true or false

Environmental & Atmospheric Sciences

Which is the most important molecule in the ecosystem?

A) oxygen B) nitrogen C) salt D) lead E) water

Environmental & Atmospheric Sciences