What exactly meant by the following tags in the xml

Hi,
I have the following tag in product_view.xml file

<record id="product_normal_form_view" model="ir.ui.view">
            <field name="name">product.normal.form</field>
            <field name="model">product.product</field>
            <field name="type">form</field>
            <field eval="7" name="priority"/>
            <field name="arch" type="xml">
                <form string="Product">
                   <group colspan="4" col="6">
                    <group colspan="4" col="2">
                        <separator string="Product Description" colspan="4"/>
                        <field name="name" select="1" />
                        <field groups="base.group_extended" name="variants" select="2" />
                    </group>

Can you please tell me in brief what exacly meant by the following tag

1: <record id="product_normal_form_view" model="ir.ui.view">
will be using the record id "product_normal_form_view" in somewhere else in some other files?

2: <field name="name">product.normal.form</field>

3: <field name="model">product.product</field>

4:<field eval="7" name="priority"/>

5: <field name="arch" type="xml">

6: <group colspan="4" col="6">
                    <group colspan="4" col="2">

Why 2 groups here ?

7: <separator string="Product Description" colspan="4"/>
                        <field name="name" select="1" />

why select=1 here for this field?

8: <field groups="base.group_extended" name="variants" select="2" />

what is meant by group=""base.group_extended" and select =2?

thanks
Bushair