2. Mangrove forest had been classified by many governments and industries alike as wastelands, or useless swamps. Do you agree with that? Why?

No

Explanation:

Mangrove forests provide many economical and ecological benefits, such as being a nursery for many small fish and organisms that depend on the habitat to survive. They also provide rookeries for birds that make their nests within these forests. These fish are then sold to be consumed, thus the economical importance.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6