The correct answers are "sugar" and "amino acids." We can find this answer within the name itself. The prefix "glyco-" relates to producing sugar (think glucose and glycogen, which are both forms of sugar), and the suffix "proteins" is exactly that: proteins (which are made up of amino acids). So, when we say glycoprotein, we can think "sugar-protein," which gives us our answer.
People who have darker skin have more melanin which is a black or dark brown pigment in the skin. When we are out in the sun our skin produces more melanin, which helps our skin be more resistant in the sun. This is why we tan.
Answer:
Microtubules, like actin filaments, are dynamic structures: they can grow and shrink quickly by the addition or removal of tubulin proteins. Also similar to actin filaments, microtubules have directionality, meaning that they have two ends that are structurally different from one another. I hope this helps :)
