Answer:
B. Absence of backbone
Explanation:
All living creatures are classified according to their shared traits. The animal kingdom has diverged into two groups: vertebrates and invertebrates. Invertebrates are animals that lack a backbone, in contrast to reptiles, amphibians, fish, birds, and mammals. One factor for invertebrates' success is their rapid reproduction. For example, sponges and corals cultivate both eggs and sperm. Social insects like ants and bees lay eggs capable of development without fertilization; these eggs evolve into workers.
Insects, in particular, thrive due to their adaptability. They are opportunistic feeders, consuming plants and animals and decomposing organic matter. They can survive in harsh settings, such as extremely hot, dry habitats. And many can fly—either to avoid predators or seek out new sources of food, water, and shelter. This is the most numerous animal group: invertebrates account for 97 percent of all creatures. There have been 1.25 million species described to date, most of which are insects, and millions more are still unknown. The total number of invertebrate species is estimated to be five, ten, or even thirty million compared to only 60,000 vertebrates.
Invertebrates are classed similarly to vertebrates based on their body form, life cycle, and evolutionary history. Classification, or taxonomy, is the process of grouping living things into logical categories. These classifications are primarily based on structure and reflect evolutionary links. Individuals and groups of related organisms can be quickly identified using standardized classifications.
For more ideas and information, you may refer to or visit this link:
https://brainly.ph/question/10025923
#BrainlyEveryday
