I claim:1. An integrated assembly, comprising:a semiconductor-containing structure comprising:a channel region between first and second source/drain regions;an extension portion of semiconductor material of the semiconductor-containing structure extending from the channel region, an entirety of the extension portion being spaced from all digit lines and all source/drain regions, and extending along one of the first and second source/drain regions;an insulative material adjacent the channel region; anda conductive gate adjacent the insulative material.2. The integrated assembly of claim 1 wherein the first and second source/drain regions comprise a first conductivity type and the extension portion comprises a second conductivity type.3. The integrated assembly of claim 2 wherein one of the first and second conductivity types being n-type and the other being p-type.4. The integrated assembly of claim 1 further comprising:a charge-storage device coupled with the first source/drain region;a digit line coupled with the second source/drain region; anda wordline coupled with the conductive gate.5. The integrated assembly of claim 4 wherein the charge-storage device and the semiconductor-containing structure being included within a memory structure.6. The integrated assembly of claim 5 wherein the memory structure is one of many memory structures which are substantially identical to one another and which are included within a memory array.7. The integrated assembly of claim 1 wherein the extension portion is coupled with a reference voltage.8. The integrated assembly of claim 1 wherein the semiconductor-containing structure comprises monocrystalline silicon.9. The integrated assembly of claim 1 wherein the extension portion and the one of the first and second source/drain regions comprise two legs of the semiconductor material of the semiconductor-containing structure extending downward from a bottom of the channel region.10. The integrated assembly of claim 1 wherein the extension portion and the one of the first and second source/drain regions comprise an intervening region comprising silicon dioxide.11. The integrated assembly of claim 1 further comprising an intervening region between the extension portion and the one of the first and second source/drain regions.12. The integrated assembly of claim 1 further comprising an insulative region between the extension portion and the one of the first and second source/drain regions.13. The integrated assembly of claim 1 further comprising an insulative region contacting at least one of the extension portion and the one of the first and second source/drain regions.14. The integrated assembly of claim 1 further comprising an insulative region contacting both of the extension portion and the one of the first and second source/drain regions.15. The integrated assembly of claim 1 wherein, from a vertical sectional view, the extension portion comprises a rectangular configuration.16. The integrated assembly of claim 1 wherein the extension portion and the one of the first and second source/drain regions comprise substantially the same shape configuration.17. The integrated assembly of claim 1 wherein, from a vertical sectional view, the one of the first and second source/drain regions comprises a rectangular configuration.18. The integrated assembly of claim 1 wherein the extension portion is coupled to a reference voltage.19. The integrated assembly of claim 1 wherein the reference voltage comprises one of ground voltage and common plate voltage.20. The integrated assembly of claim 1 wherein the extension portion comprises a dopant different from a dopant in the one of the first and second source/drain regions.21. The integrated assembly of claim 1 wherein the extension portion comprises a dopant that is the same as a dopant in the channel region.22. The integrated assembly of claim 1 wherein the extension portion is configured to replenish carriers in the channel region.23. The integrated assembly of claim 1 wherein the extension portion comprises a leg spaced from a leg comprised by the one of the first and second source/drain regions.24. An integrated assembly, comprising:a semiconductor-containing structure comprising:a vertically-extending channel region between first and second source/drain regions;a vertically-extending extension portion of the semiconductor-containing structure extending from the channel region;one of the first and second source/drain regions extending vertically from the channel region, the extension portion and the one of the first and second source/drain regions both comprising a pair of rectangular legs;an insulative material adjacent the channel region; anda conductive gate adjacent the insulative material.25. The integrated assembly of claim 24 wherein the one of the first and second source/drain regions extends along, and spaced from, the extension portion.26. The integrated assembly of claim 24 further comprising an intervening region between the one of the first and second source/drain regions and the extension portion.27. The integrated assembly of claim 26 wherein the intervening region comprises insulative material.28. The integrated assembly of claim 24 wherein the extension portion is coupled to a reference voltage.29. The integrated assembly of claim 28 wherein the reference voltage comprises one of ground voltage and common plate voltage.30. The integrated assembly of claim 24 wherein the extension portion comprises a dopant different from a dopant in the one of the first and second source/drain regions.31. The integrated assembly of claim 24 wherein the extension portion comprises a dopant that is the same as a dopant in the channel region.32. The integrated assembly of claim 24 wherein the extension portion is configured to replenish carriers in the channel region.33. An integrated assembly, comprising:a semiconductor-containing structure comprising:a channel region between first and second source/drain regions;an extension portion of semiconductor material of the semiconductor-containing structure extending from the channel region, the extension portion being laterally spaced from, and extending along, one of the first and second source/drain regions;an insulative material adjacent the channel region;a conductive gate adjacent the insulative material; andwherein the extension portion and the one of the first and second source/drain regions comprise two legs of the semiconductor material of the semiconductor-containing structure extending downward from a bottom of the channel region.34. The integrated assembly of claim 33 wherein the extension portion is coupled to a reference voltage.35. The integrated assembly of claim 34 wherein the reference voltage comprises one of ground voltage and common plate voltage.36. The integrated assembly of claim 33 wherein the extension portion comprises a dopant different from a dopant in the one of the first and second source/drain regions.37. The integrated assembly of claim 33 wherein the extension portion comprises a dopant that is the same as a dopant in the channel region.38. The integrated assembly of claim 33 wherein the extension portion is configured to replenish carriers in the channel region.