Chitukuko cha anthu ndi chofulumira kwambiri, ndipo kuchuluka kwa anthu omwe amamwa kumawonjezeka nthawi zonse. Makamaka pakugwiritsa ntchito zinthu zing'onozing'ono za tsiku ndi tsiku, tilinso kuyambira pachiyambi cha zofunikira zogwiritsira ntchito mpaka zomwe zilipo panopa kuti mukhale ndi makonda.