No, creatures do not tap when they block.
No, you cannot tap a creature with summoning sickness in Magic: The Gathering.
Yes, in a game of Magic: The Gathering, you have to tap a creature to use it to block an attacking creature.
Yes, when a creature is assigned to block an attacking creature in a game of Magic: The Gathering, it does tap as part of the blocking process.
Yes, in Magic: The Gathering, you tap your creatures to indicate that they are blocking an attacking creature.
In Magic: The Gathering, the tap target creature mechanic allows players to use a creature's abilities or attack by turning it sideways. This means the creature cannot block or use its abilities until it untaps during the player's next turn.
No, abilities that require a creature to tap or attack cannot be used if the creature has summoning sickness.
No, you cannot tap a creature with summoning sickness.
No, artifacts cannot tap on the first turn in Magic: The Gathering.
Defending creatures deal damage to an attacking creature's toughness when they block equal to their power. It's called 'blocking', not 'attacking back'. Summoning sickness has no affect on blocking. Summoning sickness is the inability of a creature to use tap (tap symbol) abilities or attack until the next turn of the owner who summoned it.
When you declare attackers, you tap your creatures. So yes, creatures do tap before damage is resolved.
Yeah. An Island
Yes, you can tap or untap a target creature during your turn in Magic: The Gathering.