Answer: The statement, atoms in the sand were moving more quickly best describes why the temperature of the sand increased.
Step-by-step explanation:
As Sun rises in the morning everyday and the heat energy radiations given by the Sun falls on a number of objects on our surroundings. As a result, the objects absorb this heat energy till afternoon due to which they become hot.
Hence, atoms of the objects gain kinetic energy due to which they move quickly. This shows that the temperature of the object (sand here) increases.
When Maria walked in the same area in the afternoon, the sand was hot as its particles have gained kinetic energy due to which they move rapidly from one place to another. Hence, sand feels more hot in the afternoon in the same area where she walked.
Thus, we can conclude that the statement the atoms in the sand were moving more quickly best describes why the temperature of the sand increased.