One explanation could be the differences in climate (environmental factors). The climate in northern Mexico could support the reproduction of the mosquito species, which is a vector of the dengue virus. Other environmental conditions that influence its endemicity could include living conditions and sanitation. The other possiblity could be that the people in the US have developed immunity for the disease, therefore, are unaffected even when infected by the virus.
Because plants go through a cycle(the cycle is seed, seedling, plant, flower and tree.) and it takes time for the plant food, water, and nutrients to go though the plant.
Covalent bond because a covalent bond is when it only shares electrons and it doesn't give or lose.
Answer: D
They often occur spontaneously, because when energy is released during a chemical reaction it does not usually happen slowly.
Answer:
A. Individuals and families ended up polluting more than factories
Explanation:
