Answer:
Crabs. Crabs belong to the subphylum Crustacean, the largest group of marine arthropods, which also includes lobster, shrimp, and krill, a shrimp-like crustacean. Crabs move sideways, walking on four pairs of legs, and holding their two legs with claws away from their body.
Some problems that might occur is that you might forget some schedules, cause there is going to be several schedules, or you might forget something, etc.
We can discuss it from many different points. However, since in this question we have to look at this only from 3 aspects, let's look at the cases of education, health and social security. In all cases, if people don't have an equal access to these basic services, they will face with problems. If you cannot have a proper education, you cannot get a better job and it will create financial instability in the future. If you don't have an access to the healthy services in case of food, sanitation and water, you will easily have health problems. If you don't have a social security, burglars will steal your possessions easily.