Which of these statements best describes a scientific theory? (2 points) It is a description of an observation which does not change over time

It is a description of an observation after research over a period of time

It is an explanation for an observation which is not based on data

It is an explanation for an observation after several valid experiments

it's not c. i took the quiz and got it wrong. so my best guess is b.

have a great day, and hope this .

answer: d. load

a river's load refers to the natural phenomena in which the sediments, rocks   stones, boulders and other deposits are removed and picked from the bottom bed of the river due to the abrasion resulted by the high speed water current.

the combining form means bone marrow or spinal cord. meio- "meiosis" myco- "mycosis" myelo- "osteomyelitis or myelogram" myo- "myositis";

the answer is: myelo- "osteomyelitis or myelogram"