Explain the biological basis for assigning all human populations to a single species. can you think of a scenario by which a second human species could originate in the future?

Molecular biology (DNA sampling) is the best proof.

Explanation:

An study published in the journal of science found that 99.9% of humans are quite similar. The  scientific team analysed DNA from 1,056 people from 52 populations in Africa, Eurasia (Europe, the Middle East, Central and South Asia), East Asia, Oceania and the Americas.

The phenotype ( visible appearance) results from a very small proportion of  differences in genetic traits, hence the concept "race" is more a cultural concept than a biological concept.

c is the correct answer!

wild parsnip is a perennial plant which reproduces rapidly in areas which have no sign of agricultural activity such roadside or at no tillage open areas. it's considered invasive because it can inhibit the growth of another plant  and its reproduction is fast. there are several harmful effects of this invasive plant although its taproot is edible since it is a member of the carrot family. wild parsnips can cause skin blistering when in contact because of the chemicals it contains, second it inhibits the growth of other plants, it will restrict the growth of animals when eaten and lastly, it drives away natural pollinators like bees.