Correct sequence of activities is:
a) Erection of formwork
b) Placing of reinforcement
c) Pouring of concrete
d) Compaction of concrete
e) Removal of formwork
f) Curing

Pouring of Concrete
The first activity in the sequence is pouring of concrete. This involves the process of placing the concrete mix into the desired area or formwork. It is important to ensure that the concrete is poured evenly and at the right consistency to achieve the desired strength and durability.

Erection of Formwork
The second activity is the erection of formwork. Formwork refers to the temporary structure or mold that holds the concrete in place during the pouring process. It provides the shape and support needed for the concrete to set and harden. The formwork can be made of various materials such as wood, steel, or plastic.

Curing of Concrete
The third activity is the curing of concrete. Curing is a critical process that allows the concrete to gain strength and durability over time. It involves providing the right conditions (e.g., temperature, moisture) for the hydration process to occur. Curing helps prevent cracking, shrinkage, and other defects in the concrete.

Removal of Formwork
The final activity in the sequence is the removal of formwork. Once the concrete has sufficiently cured and gained enough strength to support itself, the formwork can be removed. This is usually done carefully to avoid any damage to the concrete. The timing for formwork removal depends on factors such as the type of concrete, ambient conditions, and desired finish.

Correct Sequence
Based on the given activities, the correct sequence on a network would be 2-1-4-3.
- The formwork needs to be erected first to provide the necessary structure for pouring the concrete.
- Once the formwork is in place, the concrete can be poured into it.
- After the concrete is poured, it needs to cure for a certain period of time to gain strength and durability.
- Finally, the formwork can be removed once the concrete has sufficiently cured.

Explanation
The correct sequence is 2-1-4-3 because the formwork needs to be in place before the concrete can be poured. Similarly, the concrete needs to cure before the formwork can be safely removed. Therefore, the activities should follow this sequence to ensure a successful and efficient construction process.

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