The correct answer is T helper cells. <span>T helper cells are important because they have the ability to stimulate other cells to kill the foreign particles (viruses, bacteria, fungi, parasites).T helper cells help other cells in the immune response by recognizing foreign antigens and by secreting cytokines that then activate T and B cells.</span>
I think that the best phrase to fit into the blank is a "scientific theory".
A scientific theory is developed through experiments which use the scientific method, and a theory can be improved if additional data is available or if people provide suggestions which make the theory fit the data better.
Answer: This is an example of organizational heirarchy.
Explanation: These biological structures are designed in a way that the whole system consist of different parts serving its own unique purpose, making up a full functional system. It goes from; atoms, molecules,cells, tissues and organs which makes up a system. Digestive system for example is composed of atoms, molecules,cells, tissues and organs that helps to digest amd convert food into energy(ATP).
The dorsal side of the frog is the back of the frog, where the spine is.
