Answer:
Due to mixing of particles present in the upper layer of limestone with sandstone during deposition.
Explanation:
The parent layer was limestone layer which is older than sandstone layer. This sandstone layer spreads on the limestone layer because of wind. The wind moves these sandstone from other region and their deposition occurs on the limestone layer. During deposition of sandstone, some particles of limestone which are present at the surface mixes with the sandstone so that's why in sandstone layer, small and weathered pieces of limestone are present.
A reinforcement schedule is a pattern that defines how often a desired response will be reinforced.<span>
</span>A variable-ratio schedule <span>is a schedule of reinforcement where a response is reinforced after an unpredictable number of responses.</span>
<span>Fixed-interval schedules on the other hand reinforce behaviors after set time periods.</span>
<span>Herpesviridae is a large family of DNA viruses that cause diseases in animals, including humans.
When a person infected once, his immune system develops antidot against the virus, so he becomes immune for that virus for rest of his life. In other words, he can't be affected from that virus again
Hope this helps!</span>
I think it’s A, begins to change :))