I would tell them I personally don't don't have a great scientific knowledge, however, I do know many resources written by scientist with Phd's in their field of expertise. I would then point them in the right direction either books or other media.
But I would point out what Paul noted - (esp vv19-20)
The wrath of God is being revealed from heaven against all the godlessness and wickedness of people, who suppress the truth by their wickedness, 19 since what may be known about God is plain to them, because God has made it plain to them. 20 For since the creation of the world God’s invisible qualities—his eternal power and divine nature—have been clearly seen, being understood from what has been made, so that people are without excuse.
21 For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened. 22 Although they claimed to be wise, they became fools 23 and exchanged the glory of the immortal God for images made to look like a mortal human being and birds and animals and reptiles.
24 Therefore God gave them over in the sinful desires of their hearts to sexual impurity for the degrading of their bodies with one another. 25 They exchanged the truth about God for a lie, and worshiped and served created things rather than the Creator—who is forever praised. Amen.
I say this from experience as I have had friends ask for scientific proof and I end up making a hash of it. So now I point them in the right direction or get the information for them. Don't get me wrong I share with them anything I do know.
Never be embarrassed to say to someone I don't know the answer. But be willing to either get the information or point them in the right direction if they are interested.
Usually it's about evolution. I point people to reasons to believe -
https://reasons.org/
They have many youtube videos, Hugh Ross himself is an Astrophysicist Ph.D.