Keep scrolling down for answers and more stats ...
1.
. . . is larger? (area)
2.
. . . has a greater population?
3.
. . . was admitted to the union first?
Texas: 1845
California: 1850
4.
. . . is the birthplace of more presidents?
Eisenhower and LBJ were born in Texas. Nixon was born in California. (Reagan was born in Illinois.)
5.
. . . has the larger largest city?
6.
. . . has more cities with population greater than 1 million?
Texas: 6
California: 5
7.
. . . has more water area?
8.
. . . covers a greater range of temperatures? (difference between record high and record low)
9.
. . . was settled by Europeans first?
Ysleta: 1680
Santa Cruz: 1769
10.
. . . had a "Big Four" (MLB, NFL, NBA, NHL) professional sports team first?
California beats Texas in all 4:
Los Angeles Dodgers & San Francisco Giants: 1958
Houston Astros: 1962
Los Angeles Rams: 1946
Dallas Cowboys: 1960 (Or the short-lived Dallas Texans, who didn't even finish their one season in Texas: 1952)
Los Angeles Lakers: 1960
Houston Rockets: 1971
California Seals: 1967
Dallas Stars: 1993
11.
. . . has more UNESCO World Heritage Sites?
Redwood and Yosemite for California, San Antonio Missions for Texas
12.
. . . has multiple buildings over 1,000 feet tall?
13.
. . . has a city with more than 30 skyscrapers?
Houston has 38.
14.
. . . has a higher Hispanic/Latino population (by percentage)?
15.
. . . has a higher Native American population (by percentage)?
16.
. . . is "taller"? (greater distance between northernmost and southernmost points)
17.
. . . borders more U.S. states?
18.
. . . has the busiest airport?
19.
. . . has more interstate highway mileage?
Texas, unsurprisingly, is #1 in the U.S. in terms of interstate highway mileage.
20.
. . . has the larger city named Pittsburg? (city proper population)
Pittsburg, CA: 70,679
Pittsburg, TX: 4,497