What effect does the D region of the ionosphere have on lower frequency HF signals in the daytime?

What causes the ionosphere to absorb radio waves?

Two or more parts of the radio wave follow different paths during propagation and this may result in phase differences at the receiver. This "change" at the receiver is called:

A change or variation in signal strength at the antenna, caused by differences in path lengths, is called:

When a transmitted radio signal reaches a station by a one-hop and two-hop skip path, small changes in the ionosphere can cause:

The usual effect of ionospheric storms is to:

On the VHF and UHF bands, polarization of the receiving antenna is very important in relation to the transmitting antenna, yet on HF bands it is relatively unimportant. Why is that so?

What causes selective fading?

How does the bandwidth of a transmitted signal affect selective fading?

Polarization change often takes place on radio waves that are propagated over long distances. Which of these does not cause polarization change?

Reflection of a SSB transmission from the ionosphere causes: