A. The sun
Abiotic means fake or not living. Trees, grass, and people are living, also know as biotic. The sun is not living, it’s just a ball of hot gas, which is not living.
It could perhaps provide a better understanding of why dinosaurs went extinct. It could also provide some of the things Dino's ate and their average life style.
Answer is D.
Photosynthesis in plants converts solar energy into chemical energy using electrons and protons from water. ... In the energy-transduction reactions, solar energy is converted into chemical energy in the form of two energy-transporting molecules, ATP and NADPH
Calcium ions presents Ca+ binds to troponin which makes tropomyosin move out of way for myosin to attach. Cross-bridge attaches. ATP breakdown provides energy to ready the myosin head for a power stroke. Myosin head attaches to exposed binding site on actin and the power stroke is accomplished. Cross-bridge (Myosin head) springs from raised position and pulls on the actin filament. Cross bridges break, ATP binds to Cross-bridge (but is not yet broken down) Myosin heads are released from actin. As long as calcium ions and ATP are present, this walking continues until the musle fiber is fully contracted. Hope this helps!