
565 N.W.2d 12 (1997)
222 Mich. App. 732
PEOPLE of the State of Michigan, Plaintiff-Appellee,
v.
Jimmy Lee FLOWERS, Defendant-Appellant.
Docket No. 175047.
Court of Appeals of Michigan.
Submitted December 18, 1996, at Grand Rapids.
Decided April 15, 1997, at 9:05 a.m.
Released for Publication July 1, 1997.
*13 Frank J. Kelley, Atty. Gen., Thomas L. Casey, Solicitor Gen., James J. Gregart, Pros. Atty., and Judith B. Ketchum, Asst. Pros. Atty., for People.
State Appellate Defender by Susan J. Smith and Pamella R. Szydlak, for defendant-appellant on appeal.
Before BANDSTRA, P.J., and HOEKSTRA and S.F. COX[*], JJ.
HOEKSTRA, Judge.
Following a jury trial, defendant was convicted of voluntary manslaughter, M.C.L. § 750.321; M.S.A. § 28.553, in connection with the death of eight-month-old Emmet Flowers. Defendant then pleaded guilty to being an habitual offender, fourth offense, M.C.L. § 769.12; M.S.A. § 28.1084, and was sentenced to thirty to fifty years' imprisonment. Defendant now appeals, and we affirm.
Defendant first argues that he was denied due process and a fair trial by the trial court's refusal to give his requested jury instructions on what he considered to be the lesser offenses of second- and third-degree *14 child abuse.[1] The jury was instead charged on voluntary and involuntary manslaughter only, and defendant was convicted of voluntary manslaughter. A properly requested instruction for a cognate lesser included offense need be given only when two elements are satisfied. First, the principal offense and the lesser offense must be of the same class or category, which means they must have an "inherent relationship." Two crimes are "inherently related" when they serve a "common purpose" protecting the "same societal interest." Second, the evidence adduced at trial must be examined to determine whether it would support a conviction of the lesser offense. People v. Hendricks, 446 Mich. 435, 444-446, 521 N.W.2d 546 (1994).
Here, we need not examine the evidence introduced at trial because we conclude, similarly to the Court in Hendricks, that the crimes at issue are not inherently related, or of the same class and character. Id. at 448, 521 N.W.2d 546. The crimes at issue in this case, manslaughter and child abuse, do not possess a common purpose protecting the same societal interests. The societal interest in making murder, and implicitly manslaughter, a crime is deterring the killing of human beings by other human beings. See People v. Perry, 218 Mich.App. 520, 533, 554 N.W.2d 362 (1996). In contrast, we believe that the societal interest in making child abuse a crime is similar to the interests that were previously served by making child torture[2] a crime and the interests currently served by making child sexually abusive activity[3] a crime, those being the protection of children from the abuses and excesses of an adult to whose authority the children have been subordinated, see People v. Barnett, 165 Mich.App. 311, 318, 418 N.W.2d 445 (1987), and the protection of children from assaultive behavior, see People v. Ward, 206 Mich.App. 38, 42, 520 N.W.2d 363 (1994). Because we conclude that the crimes of manslaughter and child abuse are not of the same class or category, child abuse cannot be a cognate offense of manslaughter. Accordingly, we find no error in the trial court's refusal to give defendant's requested child abuse instructions.
Defendant next argues that he was denied due process and a fair trial by an improper jury instruction that characterized involuntary manslaughter as a lesser offense of murder; defendant was never charged with murder. However, defendant did not object below to the instructions given by the trial court, and thus we review this issue only if manifest injustice would result from our failure to do so. People v. Maleski, 220 Mich.App. 518, 521, 560 N.W.2d 71 (1996). Here, because the instructions as a whole fairly presented the issues to be tried and accurately stated the law, and the use of the word "murder" was not pervasive, we find that no manifest injustice will result from our failure to provide further review.
Defendant also argues that he was denied a fair trial by the admission of highly inflammatory and prejudicial autopsy photographs. We disagree. The admission of photographs as evidence is a matter within the discretion of the trial court. People v. Mills, 450 Mich. 61, 76, 537 N.W.2d 909 (1995), modified on other grounds 450 Mich. 1212, 539 N.W.2d 504 (1995). Here, we find no abuse of discretion in the trial court's decision to admit the photographs at issue, where the photographs were referred to during the pathologist's testimony and were instructive in depicting the nature and extent of the victim's injuries.
Defendant further argues that he was denied his constitutional right to an impartial jury because there were no African-Americans in the array from which the jury was drawn. After the jurors from which the jury was to be selected were brought into the courtroom, but before fourteen jurors had been selected, defendant requested that a new group of jurors be brought in because there were no African-Americans in the array. Defendant admitted below that he was not arguing that African-Americans were being *15 systematically excluded from the entire jury venire, but rather, he simply thought that he could not get a fair trial from this array.
On appeal, defendant apparently attempts to now argue that African-Americans are being excluded from the venire because none were in the array. We find defendant's argument to be without merit. While a criminal defendant is entitled to an impartial jury drawn from a fair cross section of the community, he is not entitled to a petit jury that exactly mirrors the community. People v. Hubbard (After Remand), 217 Mich.App. 459, 472, 552 N.W.2d 493 (1996). In order to show a prima facie violation of the fair-cross-section requirement, a defendant must show, among other things, that the underrepresentation of the distinctive group, in this case African-Americans, was due to systematic exclusion. Id. at 473, 552 N.W.2d 493. Furthermore, it is well settled that systematic exclusion cannot be shown by one or two incidents of a particular venire being disproportionate. Id. at 481, 552 N.W.2d 493. Here, defendant's bald assertion that systematic exclusion must have occurred because no African-Americans were in the array is not sufficient to support his challenge.
Defendant next argues that he was denied the effective assistance of counsel by his counsel's failure to have a critical witness declared incompetent to testify. Here, after reviewing the record, we do not find that the actions of defendant's counsel in this regard fell below an objective standard of reasonableness. People v. Barclay, 208 Mich.App. 670, 528 N.W.2d 842 (1995). Counsel's decision to bring out the witness' delusional tendencies on cross-examination is presumed to be sound trial strategy, and defendant has not overcome that presumption. Defendant fails to appreciate that, under MRE 601, a witness is presumed to be competent to testify.[4] Accordingly, because we believe that a motion to have the witness declared incompetent would have been futile, defendant's counsel was not ineffective for failing to bring such a motion. People v. Gist, 188 Mich.App. 610, 613, 470 N.W.2d 475 (1991).
Finally, defendant argues that his thirty- to fifty-year sentence as a fourth-offense habitual offender violates the principle of proportionality set forth in People v. Milbourn, 435 Mich. 630, 461 N.W.2d 1 (1990). Having reviewed the circumstances surrounding the offender and the offense, we conclude that the sentence imposed does not violate the principle of proportionality and does not evidence an abuse of discretion by the trial court. People v. Gatewood (On Remand), 216 Mich.App. 559, 560, 550 N.W.2d 265 (1996).
Affirmed.
NOTES
[*]  Circuit judge, sitting on the Court of Appeals by assignment.
[1]  M.C.L. § 750.136b; M.S.A. § 28.331(2).
[2]  The offense of child torture, formerly M.C.L. § 750.136a; M.S.A. § 28.331(1), was repealed and replaced by the child abuse offenses at issue in this case.
[3]  M.C.L. § 750.145c; M.S.A. § 28.342a.
[4]  The official comment to FRE 601, which is identical to our MRE 601, states: "A witness wholly without capacity is difficult to imagine. The question is one particularly suited to the jury as one of weight and credibility, subject to judicial authority to review the sufficiency of the evidence."
