Answer:
(a) Z-lines
(b) Sarcomeres
(c) The arrangement of of actin and myosin filament is called the 'double strand of pearls'
(d) The alternating strands of actin and myosin filaments gives a skeletal muscle fibre its striated appearance.
Explanation:
Each skeletal muscle is a discrete organ, made up of several kinds of tissues.These tissue includes: skeletal muscle fibres, blood vessels, nerve fibres and connective tissues. Each muscle fibre contains many myofibrils that run parallel to its length.
A sarcomere is the region of a myofibril between two successive Z- disk (or Z-lines), which is basically a 'junction points' between sarcomeres.
The striated appearance of skeletal muscle fibers is due to the arrangement of the thick and thin myofilaments within each sarcomere. And within these actin and myosin filaments are found.
