<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="zero.zd.zquestionnaire">

    <application
        android:allowBackup="false"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:screenOrientation="portrait"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity android:name=".QnaAnswerActivity"/>
        <activity android:name=".QnaBuilderActivity"/>
        <activity android:name=".LoadQnaActivity"/>
        <activity
            android:name=".QnaResultActivity"
            android:noHistory="true"/>
    </application>

</manifest>
<?xml version="1.0" encoding="utf-8"?>
<manifest
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    package="zero.zd.zquestionnaire">

    <application
        android:allowBackup="false"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:screenOrientation="portrait"
        android:supportsRtl="true"
        android:theme="@style/AppTheme"
        tools:ignore="GoogleAppIndexingWarning">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <activity
            android:name=".QnaAnswerActivity"
            android:noHistory="true"/>
        <activity android:name=".QnaBuilderActivity"/>
        <activity android:name=".LoadQnaActivity"/>
        <activity
            android:name=".QnaResultActivity"
            android:noHistory="true"/>
    </application>

</manifest>
Add noHistory on Answer Activity
Add noHistory on Answer Activity
