Which of the following is not characteristic of smooth muscle? a) the striations are due to the orderly arrangement of actin and myosin. b) neurons that innervate smooth muscles are under involuntary control. c) smooth muscle cells are uninucleate. d) smooth muscles do not contain sarcomeres. e) the thin filaments of smooth muscle fibers are attached to dense bodies.

A) The striations are due to the orderly arrangement of actin and myosin

Explanation:

Smooth muscles are non-striated involuntary muscles which are found in the walls of stomach, urinary bladder, blood vessels...Smooth muscle tissue is composed of spindle-shaped muscle cells with single central nucleus. Like the other two type of muscles (cardiac and skeletal), smooth muscles also have four main functions:

cells use diffusion to get substances in and out of themselves. that diffusion will occur across the cell membrane or the outer covering of the cell. because we are talking about the surface of the cell, surface area and volume are  important factors here. as a cell increases in size, its surface area and volume increase as well.  we call that the surface area to volume ratio (sa: vol).  but the catch is that  volume increases at a greater rate than surface  area. in other words, as a cell gets bigger, the sa: vol gets smaller. so a really small cell like bacteria is mostly cell membrane (surface) with very little contents (volume). a really big cell like an egg, is mostly insides with a super thin membrane. so what ends up happening is that the cell cannot efficiently diffuse all of the stuff it needs in/out to survive. therefore cell size is limited to about 100mm. so how do we make organisms bigger than 100mm? cells divide! by dividing and becoming multicellular, organisms are able to grow!   check out the diagrams i attached to see the effect of sa: vol. i hope this ! good luck!

stimulus is a change in the environment that causes an organism to react. the response is the reaction to the stimulus. some examples of stimuli for zebras are drought, to many predators, and bad feeding grounds such as dead grass or plants. zebras respond to stimuli just like all other living organisms