The invention claimed is:1. A memory array comprising:a vertical stack comprising:a conductive tier;an insulator tier above the conductive tier;a first stack comprising at least three select gate tiers above the insulator tier, one of the select gate tiers comprising conducting metal material, another of the select gate tiers comprising conductively-doped semiconductive material, the first stack comprising more conducting metal material tiers than conductively-doped semiconductive material tiers;a second stack comprising vertically-alternating insulative tiers and wordline tiers above the first stack, the wordline tiers comprising gate regions of individual memory cells, individual of the gate regions comprising part of a wordline in individual of the wordline tiers;channel material extending elevationally through the insulative tiers, the wordline tiers, the one select gate tier, and the another select gate tier, the channel material being a homogenous material comprising doped crystalline semiconductor material that extends continuously through the insulative tiers is directly physically contacting and directly electrically coupled with conductive material in the conductive tier;the individual memory cells comprising a memory structure between the individual gate regions and the channel material; the memory structure comprising a charge-blocking region laterally inward of the individual gate regions, a storage region laterally inward of individual of the charge-blocking regions, and insulative charge-passage material laterally inward of individual of the storage regions; a select gate in the one select gate tier and in the another select gate tier, the select gate comprising the conducting metal material in the one select gate tier and the conductively-doped semiconductive material in the another select gate tier; andan insulating material vertically between and vertically separating the conducting metal material and the conductively-doped semiconductive material proximate the channel material, the conducting metal material in the one select gate tier and the conductively-doped semiconductive material in the another select gate tier being directly coupled to one another distal the channel material.2. The memory array of claim 1 wherein the conductively-doped semiconductive material is vertically thicker than the conducting metal material.3. The memory array of claim 1 wherein the conducting metal material is above the conductively-doped semiconductive material.4. The memory array of claim 1 wherein at least one of the conductively-doped semiconductive material tiers is vertically thicker than each of the conducting metal material tiers.5. The memory array of claim 4 wherein the at least one of the conductively-doped semiconductive material tiers is at least vertically twice as thick than each of the conducting metal material tiers.6. The memory array of claim 1 wherein the first stack comprises at least four select gate tiers comprising vertically-alternating conducting metal material and conductively-doped semiconductive material.7. The memory array of claim 6 wherein the conductively-doped semiconductive material in at least one of the conductively-doped semiconductive material tiers is vertically thicker than the conducting metal material in each of the conducting metal material tiers.8. The memory array of claim 7 wherein the conductively-doped semiconductive material in each of the conductively-doped semiconductive material tiers is vertically thicker than the conducting metal material in each of the conducting metal material tiers.9. The memory array of claim 1 wherein the conductively-doped semiconductive material comprises conductively-doped polysilicon.10. The memory array of claim 1 comprising NAND.11. The memory array of claim 10 comprising CMOS under array circuitry electrically coupled to at least one of (a) the conductive tier, (b) the select gate tier, and (c) the wordlines.12. The memory array of claim 1 wherein the conducting metal material in the one select gate tier comprises elemental W; at least one of Al2O3 and HfOx being above, below, and aside the elemental W.13. The memory array of claim 1 wherein the one select gate tier is above the another select gate tier, the conducting metal material in the one select gate tier comprises elemental W and the conductively-doped semiconductive material in the another select gate tier comprises conductively-doped polysilicon.14. The memory array of claim 1 wherein the one select gate tier is below the another select gate tier, the conducting metal material in the one select gate tier comprises elemental W and the conductively-doped semiconductive material in the another select gate tier comprises conductively-doped polysilicon.15. The memory array of claim 1 wherein the first stack comprises at least three select gate tiers, a first of the at least three select gate tiers being below a second of the at least three select gate tiers, a third of the at least three select gate tiers being above the second select gate tier, the first and third select gate tiers comprising the conducting metal material which comprises elemental W, the second select gate tier comprising the conductively-doped semiconductive material which comprises conductively-doped polysilicon.16. A memory array comprising:a vertical stack comprising:a conductive tier;an insulator tier above the conductive tier;a first stack comprising at least three select gate tiers above the insulator tier, one of the select gate tiers comprising conducting metal material, another of the select gate tiers comprising conductively-doped semiconductive material; anda second stack comprising vertically-alternating insulative tiers and wordline tiers above the first stack, the wordline tiers comprising gate regions of individual memory cells, individual of the gate regions comprising part of a wordline in individual of the wordline tiers;channel material extending elevationally through the insulative tiers, the wordline tiers, the one select gate tier, and the another select gate tier and is directly electrically coupled with conductive material in the conductive tier;the individual memory cells comprising a memory structure between the individual gate regions and the channel material; the memory structure comprising a charge-blocking region laterally inward of the individual gate regions, a storage region laterally inward of individual of the charge-blocking regions, and insulative charge-passage material laterally inward of individual of the storage regions; a select gate in the one select gate tier and in the another select gate tier, the select gate comprising the conducting metal material in the one select gate tier and the conductively-doped semiconductive material in the another select gate tier; andan insulating material vertically between and vertically separating the conducting metal material and the conductively-doped semiconductive material proximate the channel material, the conducting metal material in the one select gate tier and the conductively-doped semiconductive material in the another select gate tier being directly coupled to one another distal the channel material, and wherein the conducting metal material is below the conductively-doped semiconductive material.