Final answer:
The predominant strain in the discussed cellular structure is a combination of compressive and tensile strains, with shear strain also present when a cell interacts with an elastic substrate. Homogeneous dilation, or uniform strain, predominantly occurs when the substrate has negligible stiffness.
Step-by-step explanation:
The question is concerning the predominant type of strain present in a cellular structure interacting with its substrate. In the context provided, when considering a cell with cytoskeletal (CSK) forces acting upon focal adhesions and substrate deformations, the structure primarily exhibits compressive and tensile strains. Compressive strain occurs in regions where the cell's contractile forces are pushing inwards, whereas tensile strain is found where these forces are pulling outwards, creating tension. In the cytoskeleton of developing muscle cells where striated fibers exist, constant tension leads to alternating regions of compressive and tensile strains along the substratum. Moreover, for cells on a substrate of negligible stiffness, a predominant homogeneous dilation or uniform strain (UoEo) occurs without shear. However, once substrate elasticity becomes notable, shear strain comes into play with components of strain depending on forces of the same symmetry type, suggesting the appearance of non-uniform strains such as shear.