Answer:
B) Similarities in DNA and genetic code among organisms
Step-by-step explanation:
B) Similarities in DNA and genetic code among organisms
The presence of similarities in DNA and genetic code among organisms is the piece of evidence that most strongly supports the common origin of all life on Earth. This concept is central to the theory of evolution and the understanding of how life has evolved and diversified over time.
Similarities in DNA sequences, genetic information, and the universal genetic code (the way genetic information is encoded and decoded) across all living organisms, from bacteria to humans, suggest a shared ancestry. This implies that all life on Earth originated from a common ancestor and has evolved through processes like mutation and natural selection, leading to the diversity of species we see today.
While the other options (A, C, and D) provide valuable scientific information, they do not directly address the common origin of all life on Earth as effectively as the evidence of genetic similarities. Fossil records (A) provide insights into the history of life and extinct species but may not establish a direct link to a common origin. Different atmospheric gases (C) and variations in the number of chromosomes (D) are important aspects of biology and ecology, but they are not as directly tied to the concept of a shared ancestor as the genetic evidence.