the fragment is called at the same time as the activity

I have two activities. from the first one, I call the second one, and from the second one, I call a fragment by pressing a button inside the second activity, but when I click on the button in the first activity to trigger the second activity, a fragment is immediately called

the code for calling the second activity

 val chooseActivityButton = findViewById<Button>(R.id.GoActivity)        chooseActivityButton.setOnClickListener {            val intent = Intent(this, chooseLab::class.java)            // start your next activity            startActivity(intent)        }

the code for calling the fragment

    fun onClick(view: View){        setContentView(R.layout.activity_choose_lab);        val callFragmentFirst = findViewById<Button>(R.id.call_fragment_first)        callFragmentFirst.setOnClickListener {            val fragmentTransaction: FragmentTransaction = supportFragmentManager.beginTransaction()            fragmentTransaction.replace(R.id.FirstFragmentContainer, FirstFragment()) // или .replace(R.id....)            fragmentTransaction.commit()        }    }

xml fragment conteiner

<androidx.fragment.app.FragmentContainerView        android:id="@+id/FirstFragmentContainer"        android:name="com.example.myapplication.FirstFragment"        android:layout_width="match_parent"        android:layout_height="match_parent"        app:layout_constraintBottom_toBottomOf="parent"        app:layout_constraintEnd_toEndOf="parent"        app:layout_constraintStart_toStartOf="parent"        app:layout_constraintTop_toTopOf="parent" />