Step 1: Chromosomal inversion.
Chromosomal inversions can result in tightly linked genes because the genes that are part of the inverted region will tend to be inherited together due to the altered structure of the chromosome. This prevents recombination between the genes in the inverted segment, effectively linking them.
Step 2: Explanation of the other options.
Gene duplication involves the creation of multiple gene copies, but this does not necessarily result in tight linkage. It can lead to paralogs that may diverge over time.
Deletion or insertion of an exon can affect gene structure but does not generate tightly linked genes.
The population of whirligig beetles in a lake grows or declines exponentially, i.e., \( N(t) = N(0)e^{rt} \), where \( N(t) \) is the population size at time \( t \), \( N(0) \) is the initial population size, and \( r \) is the per capita rate of population change, occurring only due to birth and death.
A researcher tracks population sizes for a year and finds the following:

Assuming that the individual birth rates remain constant throughout the year and only death rates are affected, which one or more of the following statements is/are true?
The graph shows the relationship between a variable on the x-axis and genetic diversity on the y-axis. Each point represents a species and the trend line describes the relationship across species.

Select the most appropriate variable for the x-axis.
An ornamental shrub species was brought from Japan in the early 1800s to India, where it was planted frequently in gardens and parks. The species persisted for many decades without spreading, and then began to spread invasively fifty years ago. Which one or more of the following processes could have led to it becoming invasive?
Which one or more of the following is/are greenhouse gas(es)?