Answer:b
Explanation:bipolar disorder causes emotional ups and downs
Gold is better, more valuable and silver is more common and less expensive
Answer: skeletal system
Explanation: osteoarthritis affects the cartilages of Bones.cartilages is a flexible connective tissue ,in a joint that covers the surface of the bones in the joint.it also cushions the bones from impact.
During osteoarthritis,the cartilages wears out and causes the bones in the joint to rub against each other causing swollen joints, painful joints and stiffness of joints
It occurs in joints of the knees,hips,fingers and toes.
