The diagrams below show a cross-section of an environment in which there are no earthworms present and a cross-section of an environment in which earthworms are present. Which of the following statements are true of how earthworms affect their environment according to these diagrams?
I. Earthworms increase plant yields.
II. Earthworms decrease the quantity of topsoil.
III. Earthworms are beneficial to their environments.
IV. Earthworms are detrimental to their environments.
A.
I, II, and IV only
B.
II and IV only
C.
I, II, and III only
D.
I and III only

thrombocytopenia, which is a deficiency in blood platelets, can cause bleeding and bruising in the dermis similar to senile purpura. other possible causes include: exposure to ultraviolet rays and aging skin are common causes of senile purpura. senile purpura may also be a sign of collagen loss in the skin and bones.

weathering - colorado river carves land in arizona to form the grand canyon. cracks form in a sandstone wall surrounding a house. a marble statue near the science museum is changing color due to rainfall

erosion - after a rainstorm, soil and rock piees litter the roadways. the sand dunes in the sahara desert are changing shape.

here's your answer.