CCNA Question:

Answer #1
Switch:
Switches operate at Layer 2 Data Link Layer
Address Learning
Forward / Filter decision using MAC address
Loop Avoidance
Breakup collision domains
Switches create separate collision domains but a single broadcast domain

Hub:
Hub operates at Layer 1 Physical Layer
No Filtering
No Addressing
Hub creates single collision domain and single broadcast domain
Make forwarding to all the ports when signal is arrived

Answer #2
switch is an intelligent device
switch is a layer 2 protocol.
switch is a broadcast device it is a single broadcast multiple collision device,
switch can understand MAC address
hub is broadcasting device
hub is a layer 1 protocol
hub is a single broadcast single collision device.

Answer #3
switch operate at 2 link layer and hub operate 1 physical layer

Answer #4
yes