<span>a. a natural resource and a major river</span>
C. Fishing
I think fishing would make sense due to living in a river valley.
Answer:
Poor planning, and disease
Explanation:
The obstacles that the French faced while attempting to build a canal across Panama were diseases and poor planning. The French dealt with constant outbreaks of malaria and yellow fever, which slowed construction and caused the deaths of thousands of workers. The French also did not take into consideration the geographical differences between the Suez Canal region and the Panama region. The French had succeeded in building a canal at sea level in Egypt, and they mistakenly thought a similar design would work in Panama. However, the difference in the Atlantic and Pacific Ocean sea levels, as well as the difference in elevation of the Panamanian terrain, prevented them from building a sea-level canal. The United States knew about these two problems when they undertook the project. They took preventative measures by reducing the disease-spreading mosquito population and using a canal-lock system to overcome the elevation obstacle in Panama.
D. Plateau
I'm sure there are no more.
Hope that helps! c:
Answer: two solar eclipses separated by one Saros cycle will have the same geometric characteristics (they will both be total, or partial or annular).
A Saros is a period of time of about 18 years 11 days and 8 hours and represents the time needed for the system composed by Moon, Earth, and Sun to return to its initial position.
Indeed, this is due to a natural harmony of the Moon’s motion: it takes 29.53 days to complete one orbit around Earth (Synodic Month), it takes 27.21 days to pass from the same node of its orbit (Draconic Month) and it takes 27.55 days to go from perigee to perigee (Anomalistic Month); the composition of these three motions gives one Saros of around 6585.3 days, composed by 223 Synodic Months, 239 Anomalistic Months and 242 Draconic Months (with a precision of few hours).
It has been observed that after one Saros cycle Moon, Earth and Sun are in the same initial position, therefore an eclipse occurring on day 1 of two consecutive Soros cycles would have the same geometric characteristics, which means that one Saros can be considered the periodicity of solar and lunar eclipses.
Due to the fact that a Saros is not composed by a whole number of days (we have a remainder of 8 hours), the two eclipses won’t be visible from the same location on Earth due to the rotation around its axis. It takes about 3 Soros for this to happen.
