Answer:
The system that removes waste in the blood from the body
Kidney
paired organs that clean the blood producing urine from waste
Excretory system
A group of different tissues that work Together perform a specific function
organ
A system specialized for bringing oxygen into an animal's body and removing carbon dioxide
respiratory system
The body system that recognizes and destroys pathogens and fights diseases
immune system
1. A signal is translated to cause muscle contraction
Membrane proteins may extend partway into the plasma membrane and cross the membrane entirely or be loosely attached to its inside or outside face
A. It has mass.
Air is matter, and can't be seen thus not all matter can be seen.
Any liquid or gaseous is matter (water, air, etc.)
Since it can be liquid or gaseous it doesn't have to maintain it's shape and size to be matter.
Since you did not give a list of choices,here are some reasons why l<span>iving cells cannot use heat to provide the activation energy for biochemical reactions:
</span>
>Heat can never be used to do work.
>Heat is not readily available to all living cells.
>Heat doesn't provide the activation energy for their reactions.
