Which of these statements about eicosanoid synthesis is true?

a) an early step in the path to thromboxanes is blocked by ibuprofen.
b) arachidonate is derived mainly by hydrolysis of triacylglycerols.
c) aspirin acts by blocking the synthesis of arachidonate.
d) plants can synthesize leukotrienes, but humans cannot.
e) thromboxanes are produced from arachidonate via the "linear" path.

A) An early step in the path to thromboxanes is blocked by ibuprofen.

Explanation:

Eicosanoids are signaling molecules that are produced by oxidation of  arachidonic acid or other twenty-carbon essential fatty acid. Eicosanoids are involved in immune responses: they inhibit inflammation, allergy, fever, they also regulate pregnancy, childbirth, control cell growth..

Synthesis of  prostaglandins, prostacyclin and thromboxane (subfamilies of eicosanoids) is inhibited by aspirin and some anti-Inflammatory drugs such as ibuprofen and naproxen.

b) In the population, there must be one or more traits for which individuals differ.

Explanation:

Natural selection refers to the differential process of survival and reproduction caused by phenotypic differences among individuals in particular environmental conditions. These phenotypic differences are due to genetic variation among individuals, which is the primary source on which the natural selection act. In consequence, natural selection is composed of three main components: 1-variation among individuals, 2-inheritance of the phenotypic traits that vary within a population or species, and 3- different survival and reproduction.