Useful traits have been accumulated in plants and animals over the centuries by how plants have undergone through certain phases, specifically called selection. Most of these traits are accumulated naturally but others may be acquired in the opposite way through man-made cultivation. Hope this answers your question.
Pain in two or more joints.
Raynaud's phenomenon.
Skin changes.
Swollen hands.
<span><span>Muscle weakness.</span>
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-Pressure in the pelvis/vagina/rectum
-Discomfort when straining
-Feeling like the bladder isn't fully empty after urinating
-A frequent urge to urinate
-leaking of urine
-Pain during sex
D) each parent passes only one factor for each trait to its offspring