Cell membranes are made of phospholipids to keep the cell's water (cytoplasm) in and everything else out. so your answer would be D <span />
Ribosomes produce the proteins
The skin is composed of thin membranous tissue that is quite permeable to water and contains a large network of blood vessels. The thin membranous skin is allows the respiratory gases to readily diffuse directly down their gradients between the blood vessels and the surroundings. When the frog is out of the water, mucus glands in the skin keep the frog moist, which helps absorb dissolved oxygen from the air.
A frog may also breathe much like a human, by taking air in through their nostrils and down into their lungs. The mechanism of taking air into the lungs is however sligthly different than in humans. Frogs do not have ribs nor a diaphragm, which in humans helps serve in expand the chest and thereby decreasing the pressure in the lungs allowing outside air to flow in.
In order to draw air into its mouth the frog lowers the floor of its mouth, which causes the throat to expand. Then the nostrils open allowing air to enter the enlarged mouth. The nostrils then close and the air in the mouth is forced into the lungs by contraction of the floor of the mouth. To elimate the carbon dioxide in the lungs the floor of the mouth moves down, drawing the air out of the lungs and into the mouth. Finally the nostrils are opened and the floor of the mouth moved up pushing the air out of the nostrils.
Frogs also have a respiratory surface on the lining of their mouth on which gas exchange takes place readily. While at rest, this process is their predominate form of breathing, only fills the lungs occasionally. This is because the lungs, which only adults have, are poorly developed.
<span>The two sentences that accurately describe the girls' experience with heat transfer are "Camille heats a rock in the campfire for 30 minutes, and then removes it with tongs. She greases the rock and lays the bacon strips directly on it." By heating the rocks in the campfire and laying the bacon on the rocks, the girls transferred the heat from the fire to the rocks, and the heat from the rocks to cook the bacon.</span>
Having white fur in the winter to blend in with the snow
