Answer:
Hair and nails are mostly made of protein. Your body uses protein to build and repair tissues. You also use protein to make enzymes, hormones, and other body chemicals. Protein is an important building block of bones, muscles, cartilage, skin, and blood.
Explanation:
I can’t answer how lichens arrive in a barren landscape but I can answer the 2nd part
Lichens grow when exposed to water. When wet, lichens begin to photosynthesize.
Blood first enters the heart's right atrium. A muscle contraction forces the blood through the tricuspid valve into the right ventricle. When the right ventricle contracts, blood is forced through the pulmonary semilunar valve into the pulmonary artery. Then it travels to the lungs
Answer;
Endocytosis process
The vesicular process involved in the toxin entering the neuron is endocytosis process.
Explanation;
Endocytosis is a vesicular process, that involves capturing a particle or a substance from the outside of a cell by engulfing it with the cell membrane, and bringing it into the cell.
Botulinum toxin binds to the neuronal cell membranes at the nerve terminus and enters the neuron by endocytosis.