The idea that life did not originate on Earth, but was carried here either deliberately or by natural processes, has its roots at least as far back as the Ancient greeks This idea, often referred to as panspermia, took on a scientific from in the work of various nineteenth-century authors. It later gained widespread popular appeal through the work of the Swedish chemist Svante Arrhenius, who argued that spores of life could survive in space and travel between star systems through the pressure of solar radiation.
1.Early supporters of the panspermia hypothesis
A.rejected the main elements of the hypothesis
B. argued that some primitive life has been detected on a comet.
C. pointed out that space missions will find life elsewhere.
D. suggested that the "seeds" of life may have been deliberately planted.