Can someone please review the picture and tell me things to try to fix, the threads are full of little gaps. The layers that are solid, below the threads have a tiny bit of space between them. Is it underextrusion, or a clog? The bottom layer seems good. Also I have taken a picture of grooves on the filament after the extruder. The the groove from the extruder normal? [![enter image description here][1]][1]

[1]: https://i.sstatic.net/yDWm4.jpg

Can someone please review the picture and tell me things to try to fix, the threads are full of little gaps. The layers that are solid, below the threads have a tiny bit of space between them. Is it underextrusion, or a clog? The bottom layer seems good. Also I have taken a picture of grooves on the filament after the extruder. Is the the groove from the extruder normal?