The remora attaches itself to sharks by means of its mouth. it gets free transportation and protection and also the remnants of food material that escapes the shark's mouth. the shark does not benefit and is not harmed in any way by the remora. what kind of interaction do the remora and the shark demonstrate?
a. commensalism
b. parasitism
c. mutualism

In 1959, doctors began using the powerful antibiotic methicillin to treat infections of staphylococcus aureus, but within two years, methicillin-resistant strains of s. aureus (mrsa) appeared. how did the resistant strains of s. aureus emerge? in 1959, doctors began using the powerful antibiotic methicillin to treat infections of staphylococcus aureus, but within two years, methicillin-resistant strains of s. aureus (mrsa) appeared. how did the resistant strains of s. aureus emerge? staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. over time, these resistant individuals became increasingly common. in response to treatment of staphylococcus aureus infections with methicillin, some bacteria began to synthesize cell walls using a protein that was not affected by methicillin. these bacteria survived the methicillin treatments and reproduced at higher rates than did other individuals. over time, these resistant individuals became increasingly common. in response to treatment of staphylococcus aureus infections with methicillin, bacterial populations gradually began to synthesize cell walls using a protein that was not affected by methicillin.

Choose the correct words to complete the sentences related to genetic screening. is a procedure that is used during pregnancy to detect genetic defects. is extracted from the uterus and used to identify genetic disorders?

Ascientific idea becomes valid when it is what?