Ionic bonds involve the gaining and losing of valence electrons between atoms, while covalent bonds involve the sharing of valence electrons between atoms
Answer:
peptide antigens by MHC class II molecules
Explanation:
Helper T cells are activated by peptide antigens by MHC class II molecules. These antigens express on the surface of antigen-presenting cells (APCs). After activation, the T helper cells divide and secrete cytokines to assist the immune response.
Yes, blood doping can improve your performance. Red blood cells contain lots of oxygen, thus, by filling your body with this oxygen-rich blood, you gain a lot more endurance and strength.
Answer:
The tree absorbs light energy from sunlight, converting the light energy into chemical potential energy stored in chemical bonds. The tree uses this energy to build leaves and branches and fruit. When the apple hits the ground, kinetic energy is transformed into heat energy.
Explanation:
