A plough (UK) or plow (US; both /ËplaÊ/) is a tool or farm implement used in farming for initial cultivation of soil in preparation for sowing seed or planting to loosen or turn the soil. Ploughs were traditionally drawn by working animals such as horses or cattle, but in modern times are drawn by tractors.
Polar/Nonpolar Regions. In a biological membrane, the phospholipids are organized into a bilayer, which serves as the framework in which the other components of the membrane are embedded.
The structure of cell membrane allows nonpolar molecules to  diffuse, but not polar molecules. Membrane architecture is in the  form of a phospholipid bilayer. A single phos â¦ pholipid has a head  composed of a polar NH3 group, and two tails composed of nonpolar  fatty acids.However, very small, polar molecules like water can also cross the  phospholipid bilayer due to hydrostatic pressure and concentration  gradient differences. Water will, but with some difficulty because  of it's polarity.