Marie and Pierre Curie successfully isolate radioactive radium salts from the mineral pitchblende in their laboratory
Answer:
is it true or false that new cells arise from pre-existing cells.False
Explanation:
False
A compound is always a substance because it's made out of two or more atoms bonded together. Now a substance isn't always a compound because it takes two or more elements to create a compound in a chemical reaction, ans substances can contain only one element. In other words a substance can be constructed of one type of atom. Some substances that aren't compounds are: gold and baking soda.
This mechanism allows killer T-cells to hunt down and destroy cells that are infected with germs or that have become cancerous.
The other main type of T-cells are called helper T-cells.
Helper T-cells orchestrate an immune response and play important roles in all arms of immunity.
