Answer:A) look at a spider
Explanation:
Arachnophobia is an abnormal or irrational fear of arachnids (especially spiders). In this context a sight of the spider put him to flight.
Baryonic dark matter may occur in non-luminous gas or in Massive Astrophysical Compact Halo Objects, and stars. So therefore it’s D.
Answer: It will affect muscle contraction because it is needed for the formation of muscle contraction cross-bridge.
Explanation: During muscle contraction calcium binds to troponin, a protein complex that regulates muscle contraction by exposing the binding site of actin filament. Actin filament active site is where myosin head binds to, creating a cross-bridge using enzyme ATPase to speed the reaction. Calcium ion are needed to activate troponin movement, otherwise it stays in its inactive form blocking the active site of actin filament. Without calcium ions, troponin will not move and there will be no muscle contractions.