In cell biology a centriole is a cylindrical cellular organelle composed mainly of a protein called tubulin. Centrioles are found in most eukaryotic cells. A bound pair of centrioles, surrounded by a shapeless mass of dense material, called the pericentriolar material (PCM), makes up a structure called a centrosome.
Speed is the rate at which an object covers a particular distance. According to the question, the object was moving with constant speed, there is no change in the direction as well, This imply that the object is moving with constant velocity. No external forces applied on the object. Therefore the object is moving on a straight line path.
Antibiotics disrupt essential processes or structures in the bacterial cell. This either kills the bacterium or slows down bacterial growth. Depending on these effects an antibiotic is said to be bactericidal or bacteriostatic.
