Read the passage and answer the following questions :

Organisms evolve in their respective habitats to maximize their reproductive fitness, also known as Darwinian fitness, which is often measured by a high "r" value. They adapt to the specific selection pressures present in their environment by developing the most efficient reproductive strategies. This includes variations in breeding frequency and the number and size of offspring produced.Some organisms, such as Pacific salmon fish and bamboo, exhibit a strategy known as semelparity, where they breed only once in their lifetime. In contrast, most birds and mammals follow an iteroparous strategy, breeding multiple times throughout their lives. Additionally, some species, like oysters and pelagic fishes, produce a large number of small-sized offspring, while others, such as birds and mammals, produce a small number of large-sized offspring.The desirable reproductive strategy for maximizing fitness depends on the specific conditions and selection pressures within the habitat. Ecologists emphasize that the evolution of life history traits is influenced by the constraints imposed by the abiotic and biotic components of the environment. Factors such as resource availability, competition, predation, and other ecological interactions shape the evolution of these traits. In summary, populations evolve to maximize reproductive fitness in their habitats, and the specific reproductive strategies and traits they adopt depend on the selection pressures and constraints present in their environment. Ecologists investigate these relationships to uncover the mechanisms behind the evolution of life history traits and their ecological significance.

What does the term "r value" refer to in the context of reproductive fitness? 

The rate of reproduction in a population

The r value refers to the rate of reproduction in a population. So the answer is (a).

The r value is a measure of how quickly a population is growing. It is calculated as the difference between the birth rate and the death rate. A high r value means that the population is growing rapidly, while a low r value means that the population is growing slowly.

The other options are incorrect. The ratio of offspring survival to reproductive age is called the survivorship ratio. The genetic diversity within a population is called the gene pool. The measure of adaptation to the environment is called fitness.