Cells are the basic unit of life and they are the 1st level of organization. The heart is the 3rd level. They are separated by 1 level, tissues.
Answer:
D.
Explanation:
The independent variable is the variable that goes unchanged by the others
A group of similar cells organized to perform a particular function is a "tissue."
A B C OR D it would most likely be D all of the above :)
Hope this helps right here, A babyy animal knowss what to do after birthh just becausee it'ss just a naturall formm of instincts , i think
- hope this have helped you in anyway .