The first vertebrates to evolve lacked jaws and had skeletons made from a strong flexible tissue called cartilage.As shown in the figure below,________ are a modern example of this ancient group of vertebrates known as jawless fishes. 
Definitions:
Fibrosis
The formation of excess fibrous connective tissue in an organ or tissue in a reparative or reactive process.
Smooth Muscle Tone
The continuous and passive partial contraction of smooth muscles, which helps maintain functions like blood pressure and digestion.
Action Potentials
Short-lasting events in which the electrical membrane potential of a cell rapidly rises and falls, following a consistent trajectory.
Plasma Membranes
The lipid bilayer surrounding a cell, regulating the passage of substances in and out of the cell.
Q2: During the conquest of Mexico,outbreaks played an
Q2: What is the age-specific mortality rate
Q3: Which of the following statements is
Q27: According to the phylogenetic tree below,which of
Q30: lobed fins<br>A)A<br>B)B<br>C)C<br>D)D<br>E)E<br>F)F<br>G)G<br>H)H<br>I)I<br>J)J
Q38: Mammalia<br>A)genus<br>B)order<br>C)family<br>D)kingdom<br>E)species<br>F)class<br>G)phylum
Q60: All primates have opposable thumbs.This means the
Q72: According to the infographic shown below,ninety-five percent
Q74: The three sea urchin species shown below
Q79: There are three major groups of fungi: