Which of the following best demonstrates the unity among all living organisms?
a. Structure correlated with function
b. DNA and a common genetic code
c. Emergent properties
d. Natural selection

Verified step by step guidance

1. Understand the concept of 'unity among all living organisms,' which refers to the shared characteristics that connect all forms of life despite their diversity.
2. Review the options provided: (a) structure correlated with function, (b) DNA and a common genetic code, (c) emergent properties, and (d) natural selection.
3. Analyze option (a): 'Structure correlated with function' refers to how biological structures are designed to perform specific functions, but this concept does not directly highlight the unity among all living organisms.
4. Analyze option (b): 'DNA and a common genetic code' is a fundamental feature shared by all living organisms, as the genetic code is universal and used by all life forms to store and transmit genetic information.
5. Compare the remaining options (c and d): 'Emergent properties' describe how complex systems arise from simpler components, and 'natural selection' explains the mechanism of evolution, but neither directly demonstrates the unity among all living organisms as clearly as the shared genetic code in option (b).

Key Concepts

Unity of Life

The unity of life refers to the shared characteristics and common ancestry of all living organisms. Despite the vast diversity in form and function, all life on Earth shares fundamental biological processes and structures, indicating a common origin. This concept underscores the interconnectedness of life and is foundational in understanding evolutionary biology.

DNA and Genetic Code

DNA (deoxyribonucleic acid) is the hereditary material in all living organisms, containing the instructions for development, functioning, growth, and reproduction. The universal genetic code, which dictates how sequences of nucleotides in DNA are translated into proteins, is remarkably consistent across different species. This commonality in genetic coding is a key piece of evidence for the unity of life.

Natural Selection

Natural selection is a mechanism of evolution proposed by Charles Darwin, where organisms better adapted to their environment tend to survive and reproduce more successfully. This process leads to the gradual evolution of species and highlights the diversity of life. However, it also emphasizes the shared ancestry of organisms, as all species evolve from common ancestors through this process.