The possibility to answer is C.
Contour plowing, the contour lines of the terrain are being traced, and curves are considered the contour lines in this instance. Contour plowing is always done parallel.
When an individual is dehydrated, his or her intravenous fluids should be isotonic, because either a hypertonic or hypotonic IV would both cause damage to the individual’s red blood cells. Isotonic solutions are used: to increase the EXTRACELLULAR fluid volume because of blood loss, surgery, dehydration, fluid loss that has been loss extracellularly.
7. Succession, 6. Extinction, 5. Niche, 3. Ecosystem, 2. Population, 1. Habitat, 4. Environment, 8. Community