The correct answer is D.
Seafloor spreading is a process of creating seafloor crust out of volcanic materials that are emerging from the Earth's core at the mid-ocean ridges.
This is made possible by the moving of Earth's tectonic plates.
When a specimen is to be observed under the light microscope, scientists usually stain the specimens using different type of chemical stains depending on the type of specimen to be observed. Staining of specimen make the structures that are to be observed in the specimen very visible under the microscope, this make it easy for scientists to observe their structures.
Answer:
It effects the body by causing symptoms like muscle aches, low-grade fever, headaches, sometimes rashes, swelling of the lymph glands may also occur, and flu-like illness. These are symptoms after a few weeks of being infected.