The Precambrian-Cambrian boundary represents the first appearance of:

a. vertebrates.
b. amphibians.
c. reptiles.
d. animals with skeletons.
e. animals with soft bodies.


D

Environmental & Atmospheric Sciences

You might also like to view...

Sinkholes only form very gradually

a. True b. False Indicate whether the statement is true or false

Environmental & Atmospheric Sciences

What is true about unanchored sand dunes?

A. Wind erosion occurs on the leeward slope. B. Wind deposits sand on the leeward slope. C. Dunes move against the direction of wind. D. Wind erosion forms the dune’s slip face. E. Wind deposits constantly change dune shape.

Environmental & Atmospheric Sciences

Calculate the change in sea level (in km) if the ice sheets melted, and

write your result below (see sidebar). What will be an ideal response?

Environmental & Atmospheric Sciences

One of the general concerns about the widespread use of transgenic organisms is the

A) spread of these transgenic traits to other organisms. B) need to apply more pesticides to crops and plow the soil twice a year. C) reduced yields that result from using bioengineered organisms. D) pressure to bring more land into agricultural production.

Environmental & Atmospheric Sciences