The phylogeny of the family Hominidae indicates that living humans share a most recent common ancestor with the lineage including chimpanzees and bonobos. Modern humans and gorillas share a more distant common ancestor. Gorillas, chimpanzees and bonobos walk on the knuckles or fists of their forelimbs while humans do not. What trait that evolved in the Tribe Hominini lineage explains this difference?

The trait that evolved in the Tribe Hominini lineage explains the given difference is called;

Bipedalism

In the history of the phylogeny of the family, it shows the history of formation of organisms.

Now, we are told that Gorillas, chimpanzees and bonobos walk on the knuckles or fists of their forelimbs while humans do not.

Now, this motion of movement described in the question is one of terrestrial locomotion where an organism moves by means of its two rear limbs or legs.

This manner of movement is called Bipedalism.

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The trait of walking on the knuckles or fists of their forelimbs explains this difference.

Explanation:

A phylogenetic tree can be described as a diagram which shows the ancestral history of organisms, It helps us to recognize which organisms might have had a common ancestor in the near past.

Hominini can be described as a primate of a taxonomic tribe  which comprises those species regarded as human or directly ancestral to humans.

The above description shows that humans got separated from these organisms because these organisms had the trait of walking by knuckles.

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explanation: