Answer:
In the course of evolution mammals are the animals which are evolved recently as compared to other groups such as fish, amphibians, or reptiles.
In addition, fur or hairs on body, mammary glands, middle ear bone, warm-blood, et cetera are the characteristics of mammals.
These characteristics were evolved during the course of evolution; they were not present in ancestral organisms.
However, tail, gill pouches, et cetera are characteristics of our ancestral groups. Thus, characters can be sometimes observed in mammals.
But mammals characteristics can not be observed in organisms which were evolved before mammals such as fishes, amphibians, reptiles, et cetera.
Phosphorous: Also known as phosphoric acid and phosphate, phosphorous, which is in cola and many processed foods, can interfere with calcium absorption.
Insoluble fiber: This type of fiber, such as the kind in wheat bran, reduces calcium absorption
Foods with high levels of oxalic acid include spinach, collard greens, sweet potatoes, rhubarb, and beans and this will interfere with calcium absorption.
The correct answer is 4) A dichotomous key is complete when each organism stands alone.
The statement about a dichotomous key that is true is "A dichotomous key is complete when each organism stands alone."
Scientists have the need to correctly identify organisms, animals, plants, and objects. For that to happen, they have dichotomous keys.
These tools help them to identify and give a correct name that differentiates from other objects and organisms. So the most important thing about the dichotomous key is the fact that it identifies an organism, species or objects with its scientific name.