Adipose tissue is one of the main types of connective tissue.  It is also known as fat, and is a loose connective tissue composed mostly of adipocytes.  

Cartilage is a flexible connective tissue found throughout the body in places such as the ear, nose, bronchial tubes, and intervertebral discs. It is not as hard as bone, but it is stiffer and less flexible than muscle. Cartilage is composed of specialized cells named chondrocytes. These cells produce and maintain the cartilaginous matrix, which is composed of collagen and proteoglycan. 

Relay of electrical signals is performed by the nervous system, not by connective tissue. 

Connective tissue is responsible for binding organs together and is defined by a set of common cells suspended in an extracellular matrix. Blood, bone, adipose, and ligaments are all considered connective tissue.

Epithelial tissue covers body surfaces, nervous tissue detects changes in the environment, and muscular tissue generates force by contracting.

Connective tissue has a wide variety of functions, including all of the given answer options. Along with epithelial tissue, connective tissue is one of the more versitile tissues in the body. Bone, cartilage, and fibrous connective tissue provide support and protection to organs. Loose connective tissue and fibrous connective tissue are common components of basement membranes and connective structures that bind organs together; ligaments and tendons perform similar functions for muscle and bone connections. Adipose tissue (fat) is used to store energy for long periods.

Connective tissue is mostly extracellular material, with cells scattered sparsely throughout. One of the main components of the extracellular material involved in most connective tissue is collagen, a fibrous protein that plays a structural role. 

Most connective tissue cells are fibroblasts (fiber-producing cells), which secrete the proteins that comprise the extracellular matrix. All blood cells are considered connective tissue, including white blood cells and plasma cells (mature B-lymphocytes). Adipocytes (fat cells) are responsible for connecting and surrounding body organs, and providing structural support, as well as storing energy for the body. 

Blood cells, also called hematocytes, fall into three general categories: red blood cells (erythrocytes), white blood cells (leukocytes), and platelets (thrombocytes).  

Erythrocytes primarily carry oxygen and collect carbon dioxide through hemoglobin. Leukocytes are involved in the immune system, defending the body against infections and foreign materials. One type of leukocyte is a neutrophil. Thrombocytes are very small cell fragments that are involved in hemostasis (stopping bleeding) and the formation of blood clots.

Pinocytes do not exist. However there is a mechanism called pinocytosis by which cells ingest extracellular fluid and its contents.  

There are three primary types of muscle. Cardiac muscle is composed of striated, mono-nucleated cells and is found in the heart. Additionally, cardiac muscle cells are joined by intercalated discs and are capable of auto-regulating contraction without nervous stimulation.

Skeletal muscle is composed of striated, multinucleated cells and is found around the bones of the body. Skeletal muscle is under voluntary control and is primarily responsible for causing movement of bones and limbs.

Smooth muscle is composed of non-striated, mono-nucleated cells and is found around the organs and blood vessels of the body. Smooth muscle helps control blood flow, digest food, and contract the diaphragm.

Skeletal muscle is striated due to its sarcomere composition. The bands of each sarcomere align, giving the muscle its striped appearance. Skeletal muscle cells have multiple nuclei, allowing them to synthesize more RNA (and proteins) to maintain muscle tone.

Intercalated discs are only found in cardiac muscle, and help with cell adhesion and signal transduction.