When you are evaluating your material for an informative speech, you should be particularly careful to make sure the material is not
biased
ethical
specific
complex

a) Biased. Because you stop been arbitrary and take a side whether positive or negative about the object of study. Losing Objectivity and arbitrarily. And when you research in order to know about a topic you have to know the good and bad to build a strong hypothesis with enough arguments, to be capable of prepare a defence in case someone wants to false it.

Explanation:

The concept biased means that the posture is inclined to one side: positive or negative, without being objective. Thus, an informative speech has to be objectively neutral or arbitrary: which means without taking a posture to speak in favor or against the phenomenon or object of study. Objectivity is considered, to tell the truth about something including positive and negative. When your objective is to inform, you have to describe as much as you can the object or phenomenon. In contrast when you want to take a posture to support or false that phenomenon you can take a side.

ludwig van beethoven (/ˈlʊdvɪɡ væn ˈbeɪt(h)oʊvən/ (about this soundlisten); german: [ˈluːtvɪç fan ˈbeːthoːfn̩] (about this soundlisten); baptised 17 december 1770[1] – 26 march 1827) was a german composer and pianist. a crucial figure in the transition between the classical and romantic eras in classical music, he remains one of the most recognized and influential of all composers. his best-known compositions include 9 symphonies; 5 piano concertos; 1 violin concerto; 32 piano sonatas; 16 string quartets; a mass, the missa solemnis; and an opera,

fidelio. his career as a composer is conventionally divided into early, middle, and late periods; the "early" period is typically seen to last until 1802, the "middle" period from 1802 to 1812, and the "late" period from 1812 to his death in 1827.

beethoven was born in bonn, then the capital of the electorate of cologne and part of the holy roman empire. he displayed his musical talents at an early age and was taught by his father johann van beethoven and composer and conductor christian gottlob neefe. at the age of 21 he moved to vienna, where he began studying composition with joseph haydn and gained a reputation as a virtuoso pianist. he lived in vienna until his death.

by his late 20s his hearing began to deteriorate and by the last decade of his life he was almost completely deaf. in 1811 he gave up conducting and performing in public but continued to compose; many of his most admired works come from these last 15 years of his life, commonly known as his "late" period.