Texas Republican Sen. Ted Cruz sparred with New York Democratic Rep. Alexandria Ocasio-Cortez over several unanswered science questions.

The spat began Thursday when Ocasio-Cortez criticized President Donald Trump for putting Vice President Mike Pence in charge of the task force responding to Coronavirus.

Mike Pence literally does not believe in science. It is utterly irresponsible to put him in charge of US coronavirus response as the world sits on the cusp of a pandemic. This decision could cost people their lives. Pence’s past decisions already have. https://t.co/NhMPOusOWm — Alexandria Ocasio-Cortez (@AOC) February 27, 2020

Cruz responded by asking Ocasio-Cortez, “As you are speaking as the oracle of science, tell us, what exactly is a Y chromosome?” (RELATED: ‘They’re Not Ted Cruz, Believe Me’: Trump Mocks Democratic Primary Debates)

As you are speaking as the oracle of science, tell us, what exactly is a Y chromosome? https://t.co/t4XVVzWr3A — Ted Cruz (@tedcruz) February 27, 2020

Ocasio-Cortez fired back, insulting Cruz and touting her own scientific prowess and resume.

Sen. Cruz, while I understand you judge people’s intelligence by the lowest income they’ve had, I hold awards from MIT Lincoln Lab &others for accomplishments in microbiology. Secondly, I’m surprised you’re asking about chromosomes given that you don’t even believe in evolution. https://t.co/vOIwJhpl7q — Alexandria Ocasio-Cortez (@AOC) February 28, 2020

Sincerely,

an Intel global finalist,

a fmr multi-year intern for Sen. Kennedy,

a cum laude dual major in Economics & International Relations,

a fmr Educational Director for national organization,

Who to you is “just a bartender,”

And also your colleague.https://t.co/9ktAgXFXDE — Alexandria Ocasio-Cortez (@AOC) February 28, 2020

Cruz challenged Ocasio-Cortez directly then, pointing out the fact that he had asked her three scientific questions that she had ignored in favor of sharing her “resume & ad hominem attacks.”

We see evolution every day: the Dem party is rapidly evolving into an angry, anti-science socialist ideology. You insulted Pence & I asked you 3 real Qs re science. You ignored all 3 & responded w/ your resume & ad hominem attacks. Instead of insults, address the substance. https://t.co/QhyqRJOrii — Ted Cruz (@tedcruz) February 28, 2020

Cruz then repeated all three of the questions, beginning with the one about the Y chromosome.

2/x To reprise, science Q1 was “tell us, what exactly is a Y chromosome?” — Ted Cruz (@tedcruz) February 28, 2020

“Science Q2 was ‘at what age of gestation does science tell us that an unborn child feels physical pain?'” Cruz’s second question was meant to challenge the Democratic Party’s position allowing abortion through all nine months of pregnancy for any reason.

3/x Science Q2 was “at what age of gestation does science tell us that an unborn child feels physical pain?” — Ted Cruz (@tedcruz) February 28, 2020

“And Science Q3 was ‘of the 195 countries on planet Earth, which country produced the greatest total reduction in CO2 emissions in 2019?'” Cruz’s final question attacked the Green New Deal and the fact that the United States is not the primary offender with regard to CO2 emissions.

4/x And Science Q3 was “of the 195 countries on planet Earth, which country produced the greatest total reduction in CO2 emissions in 2019?” — Ted Cruz (@tedcruz) February 28, 2020

5/x I await you’re engagement on the actual substance, as a colleague as you noted, hopefully without the insults. — Ted Cruz (@tedcruz) February 28, 2020

At the time of publication, Ocasio-Cortez had not responded to any of the questions.