The phrase "are most dependent on" is correct and usable in written English.
You can use it when discussing the reliance or necessity of something in relation to another factor or element.
Example: "Many species in the ecosystem are most dependent on clean water for their survival."
Alternatives: "are heavily reliant on" or "are primarily reliant on".
The students who are most dependent on their parents may be dangerously unprepared for the inevitable stresses of college life.
France and Lithuania are most dependent on nuclear power, with reactors supplying about three-quarters of their needs.
The rally has been led by cyclical stocks, those that are most dependent on economic growth.
"The economy of the city would be devastated," the mayor said, adding that the city's poorest residents would suffer most because they are most dependent on mass transit.
Our chart shows which of Libya's main export markets are most dependent on it for their oil.
No wonder rich people are on the whole conservative: the most ferocious defenders of the status quo are usually those who are most dependent on the system.
And at those special moments, when those I love most were most dependent on others, the National Health Service gave my family superb care.
But the Rangers are perhaps the team whose playoff fate was most dependent on the player they lost, right fielder Nelson Cruz, who received a 50-game suspension.
But they are having a negative effect on jobs in the private sector, according to an analysis of the industries whose head count is most dependent on federal funds.
Among the developed countries, the best performers for the decade were those that were most dependent on natural resources, whose prices generally rose, in part because of additional demand from expanding economies in emerging markets.
The rejection will be a blow to all three companies involved, with Amylin's shares expected to be hit hardest since it is most dependent on Bydureon's success.
