What is a cell membrane composed of?

If assuming tasting ptc as a simple gene trait,what other genotype would you select to put in this missing genotype box that could result in this phenotype

Overtime the pond slowly becomes more acidic due to the release of chemicals from a nearby factory. which of the organisms would most likely survive the change to their environment?

Which of the following is an eon in the time scale? phanerozoic proterozoic archean all of the above