The accepted model of plasma membrane structure proposed by Singer and Nicolson is called the:

1. Several models of membrane structure were proposed during the twentieth century. 2. The one that survived describes a membrane whose parts drift within a two-dimensional sheet. 3. The explanation proposed by Singer and Nicolson is called the fluid mosaic model. 4. The railroad track description belongs to the earlier Davson and Danielli picture. _Source: OpenStax Biology for AP(R) Courses (CC BY 4.0), Ch 5 'Structure and Function of Plasma Membranes', sections 5.1-5.4_