Storm systems often move across the Unites States, beginning on the West Coast and moving eastward. Which of the following directly affects the path of the large air masses that from these systems? trade winds in the lower atmosphere

the amount of ice near the North Pole

jet streams winds in the upper atmosphere

the Gulf Stream current in the Atlantic Ocean

When first used in medicine in the 1940s, penicillin was uniformly effective in killing the bacterium staphylococcus aureus. today, natural selection in staphylococcus aureus populations has led to an increase in antibiotic-resistant alleles.
Staphylococcus aureus is a Gram-positive, round-shaped bacterium and common cause of skin infections.
Antibiotic resistant strains of S. aureus such as methicillin-resistant S. aureus (MRSA) is problem in medicine.