C. elaborate why was trade crucial to the survival
of ghana, mali, and songhai

d is the correct answer.

b is incorrect because it makes food by itself

c is incorrect because us humans don't know how to produce their own food using the sun like plants.

a is incorrect because consumers can depend on carnivores for eating food for consumers to eat the dead organism. same thing with omnivores.

freeborn women in ancient rome were citizens (cives), but could not vote or hold political office. because of their limited public role, women are named less frequently than men by roman historians. but while roman women held no direct political power, those from wealthy or powerful families could and did exert influence through private negotiations. exceptional women who left an undeniable mark on history range from lucretia and claudia quinta, whose stories took on mythic significance; fierce republican-era women such as cornelia, mother of the gracchi, and fulvia, who commanded an army and issued coins bearing her image; women of the julio-claudian dynasty, most prominently livia (58 bc-ad 29), who contributed to the formation of imperial mores; and the empress helena (c.250–330 ad), a driving force in promoting christianity.

women in the ancient greek world had few rights in comparison to male citizens. unable to vote, own land, or inherit, a woman’s place was in the home and her purpose in life was the rearing of children. this, though, is a general description, and when considering the role of women in ancient greece one should remember that information regarding specific city-states is often lacking, is almost always from male authors, and only in athens can their status and role be described in any great detail. neither are we sure of the practical and everyday application of the rules and laws that have survived from antiquity. we do know that spartan women were treated somewhat differently than in other states. for example, they had to do physical training like men, were permitted to own land, and could drink wine.

i believe the answer is:   psychological  experiment

in this experiment, wilhelm wundt became the first person that implement scientific method in analyzing the pyschological phenomenon.

due to this result, wilhelm wundt also able to make psychology to be acknowledged as a separate scientific field from biology.