The ground beneath the nelsons house is beginning to sag and sink. what is a possible explanation

The most probable and logical possibility would be that the groundwater beneath Nelson's house has been exhausted.

Explanation:

If there is a groundwater bed lying below the foundation of the house, it is necessary for the groundwater to stay intact in its place because if it is extracted from beneath the foundation of the house, the vacant space left after the water gets exhausted would create a cavity which might shrink due to the weight of the house structure above it and may cause the house to sag an sink.

temperatures get warmer — and heatwaves are more common. nothing says summer like warm weather. this rise in temperatures is caused by the tilt of the earth's axis. our planet doesn't sit perfectly straight as it spins — it has a slight lean of approximately 23.5 degrees with respect to the sun, called the axial tilt.

explanation:

7.03-1.70=5.33 and 6.80+5.09=11.89 and 5.5-3.01=2.49