Answer:
Many cells are specialized. They have structure that are adapted to their function. For eg : muscle cells bring parts of the body together. They contain protein fibres that can contract when energy is available, making the cells shorter.
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a. Cassegrain focus</span> is the focal arrangement in a Cassegrain reflector used in optical telescopes and radio antennas. The primary mirror is a concave mirror, and the secondary mirror that reflects the focused light back to it is a convex mirror.
