Question

Observe the sidewalks shown. You can see that the concrete blocks have gaps at regular intervals. Can you think why?​

Answer 1

Answer:

Explanation:

There are gaps left between slabs of concrete so when the concrete expands and contracts because of changing temperature the concrete slab wont crack and the reason they fill it with tar is because it keeps water from running in the cracks and undermining the slabs while at the same time remaining squishy enuff to allow for the movement of the slab