Explanation:
Fixed> materials for used production, machinery
Variable> Employee salary, wages, rent
Answer:
The hydrophobic core of the membrane does not allow the charged particles to pass through it.
Explanation:
The inner core of the membrane is made up of hydrophobic fatty acid tails of phospholipids. Due to this, some substances such as large, charged and polar particles cannot cross the membrane. This is why Na+ with a positive charge cross the membrane with the help of transport proteins only. On the other hand, molecular oxygen (O2) has a small structure and does not carry any charge. Therefore, it can cross the membrane without any help of transport proteins.
The correct answer is convection because the campfire warms the air around the person.
Convection refers to the transfer of mass motion of a fluid like water or air when the heated fluid is made to be carried away from the heat source, that is, carrying energy with it. Convection takes place when particles with an ample of heat energy in a gas or liquid move and occupy the place of constituents with less heat energy.
Heat energy is conducted from hot places to cooler places by the process of convection.
