Answer:
Speciation, it's the formation of a new organism in evolution
Oxygen, it takes in Carbon Dioxide and releases Oxygen as a waste :)
The answer is B. Paleozoic
This era was the first era where insects, amphibians, and reptiles roamed the Earth.
Hope this helps!
Answer: Substances that are protein based cannot cross the lipid cell membrane, but can exert their effect by binding to the proteins based receptors present on the lipid bilayer.
Explanation:
Hormones such as calcitonin , Parathyroid hormone and pituatry horomones are proteins and water soluble.They cannot cross lipid bilayer but can bind to ligand binding protein receptors.
These receptors are protein macromolecules that are specific in nature for specific hormones.
After binding to the receptors, these hormone-recpetor complexes activate second messengers and regulate the downstream effects.
