Which of the following steps has not yet been accomplished by scientists studying the origin of life?
a. synthesis of small rna polymers by ribozymes
b. formation of molecular aggregates with selectively permeable membranes
c. formation of protocells that use dna to direct the polymerization of amino acids
d. abiotic synthesis of organic molecules

The correct answer is option c. "formation of protocells that use DNA to direct the polymerization of amino acids".

Explanation:

The polymerization of amino acids is a complex biological function that involves multiple proteins and cofactors working together at different locations in the cell. Even though there are some scientific advances in the production of synthetic protocells (cell like structures made from synthetic particles), the formation of protocells able to synthesize amino acids from DNA directly has not been accomplished.

endo:

regulates body hormones, aldosterone, vasopressin

neural:

signal, regulates body using electric signals, reflex

endo has to do with hormones; aldosterone and vasopressin are both hormones. i also had this question and got it right : d