Which phrase best defines a galaxy? tightly packed group of older stars large grouping of more than two stars loose, disorganized star cluster held together by gravity large collection of stars, gas, and dust held together by gravity

15 ! come and answer! a(n) disease is caused by a pathogen and can spread among organisms. a infectious b noninfectious c toxic d contaminated

Vaccines are weakened forms of disease causing microorganisms, which are given to patients to prevent disease. after the vaccine is administered, the immune system responds by creating a(n) to recognize the a.) antibody, antibiotic b.) antigen, antibody c.)antibiotic, antibody d.)antibody, antigen

Which type of respiration takes place when there is no oxygen present? a. anaerobic b. mitochondrial c. cellular d. aerobica. anaerobic