<span><span>Porosity is the amount of empty space in a rock or other earth material (like sand) - in other words, it's how much water a material can hold.
Permeability refers to how well water flows through a material - the flow is controlled by how large the pores are and how well connected the pores are in a given object.</span><span>Therefore, there these are two primary factors that limit the movement and the amount of water (or other fluids) retained in rocks/sedimentary materials.</span></span>
Answer:
(D). In dry climates, it can become a dry wash (also called wadi or arroyo)
Explanation:
Ephemeral stream is a stream that flows only briefly during and following a period of rainfall in the immediate locality, Ephemeral streams have less flow in response to rainfall than intermittent streams, are typically shallow, and have flowing water for brief periods.
In dry climates, ephemeral streams become a dry wash, As a result of a high-intensity thunderstorm, the dry channel of an ephemeral stream, which often carries flow for just a few days each year, can be dramatically transformed into a raging torrent of muddy water and debris in a matter of minutes. The flow recedes almost as quickly, and the channel is dry again.
The answer to your question is,
Two. The twin towers both collapsed.
-Mabel <3