The level of taxonomic study related to biological aspects of taxa, inclusive of intraspecific populations, speciation, evolutionary trends and rates is

The correct option is gamma taxonomy.

Taxonomy, the science of naming, describing, and classifying organisms, is generally divided into three main hierarchical levels to describe the depth of biological and evolutionary understanding: alpha, beta, and gamma taxonomy.

Let us break down these levels to understand why gamma taxonomy is the correct answer:
1. Alpha taxonomy: This is the primary or basic level of taxonomy. It is concerned solely with the identification, description, and naming of species based on morphological features.
2. Beta taxonomy: This level goes a step further by arranging species into hierarchical systems of classification (genera, families, orders, etc.) based on their relationships, primarily focusing on structural similarities and differences.
3. Gamma taxonomy: This is the most advanced and comprehensive level of taxonomic study. It goes beyond mere identification and arrangement. Gamma taxonomy deals with the biological aspects of taxa, including the study of intraspecific populations (variation within species), speciation (how new species arise), evolutionary trends, and the rates of evolutionary changes. It incorporates evolutionary biology, genetics, and ecology to understand the evolutionary history and relationships of organisms.

Therefore, the level of taxonomic study that is inclusive of intraspecific populations, speciation, evolutionary trends, and rates is indeed gamma taxonomy.