Mules, the offspring of donkeys and horses, are commonly used as pack animals. Despite the existence of mules, horse
and donkeys are considered separate species,
Which discovery would change that thinking and define horses and donkeys as the same species?
O
O
O
O
if mules looked more like donkeys
if mules looked more like horses
if mules could produce offspring
if mules were sterile

If mules could produce offspring.

Explanation:

Even though horse and donkey produce mule, they are still regarded as different species because the mule produced cannot produce an offspring of its own.

The only why they can be considered as same species is if the mule can also reproduce.

the correct answer is 4) heat and pressure

metamorphic rocks arise from transformation of existing rocks types, in a process called metamorphism. during metamorphism the original rock(prolith) change into metamorphic rock by heating (150-200c) and pressure of more than 1000 bar. the original rock can be sedimentary, igneous, or existing metamorphic rock.