Let's discuss first about difference between micro- and macro-nutrients. Micronutrients are those which are needed in small quantities and their function is not that vast. But macronutrients are the ones which control all the metabolic cycles of the cell, so they are needed in large quantities. This is the basic difference between the two terms.
Proteins are macro-nutrients because they are needed in large amount, as they are involved in some of the most important functions of our body. For example, proteins act as enzymes, involved in immunity, maintaining homeostasis of the body, etc. That is why they are considered as macronutrients.
I disagree with this statement. Asexual organisms are at a lower risk for extinction due to the fact that they do not need a partner to procreate. They have an easier time making offspring.