Answer:
Some scientists believe that there were huge fires and the skies were dark and full of pollution due to a meteor exploding and killing off the dinosaurs, and if it's true that this occurred, the Ostrich evolved to be a land animal due to it being too dangerous in the air for them. The long neck may have developed to help them get food that was higher up which is the same speculation for the Giraffe. To stay on land they had to be stronger, bigger, and faster than they were in flight.
Explanation:
1. skin tears saliva stomach acid with all produce friendly bacteria. 2. active immunity is when one has a disease or live pathegon and is immune to it afterwards. unlike passive immunity
Photosystems 1 and 2 are here
Response - a reaction to something
Adaption - adapting to something.
Example : if you're adapting to a new diet, your reaction would be different than what you normally eat
Answer:
The answer is "ligand-gated channel".
Explanation:
The action that is described in the question is an example of a "ligand-gated channel".
The ligand-gated channels are found in the muscles and they are membranes made out of ion-channel proteins which chan be controlled by certain released chemicals into the medium to open them up or closed them and allowing the sodium, potassium or calcium ions to pass through.
I hope this answer helps.