Biology Questions

Corneas are only tissues that don’t have blood vessels. Tissues are the level cellular organization in the human body which lies between cells and a complete organ. Tissues of similar cells group together to form an organ.

There are four types of tissues. They are :

Epithelial,

Connective,

Muscular, and

Nervous tissue.

The striations are a result of the A bands of sarcomeres appearing as relatively wide, dark stripes under the microscope, which alternate with narrower, lighter colored stripes formed by the I bands. 

The striations of skeletal muscle are created by the organization of actin and myosin filaments resulting in the banding pattern of myofibrils.