Una especie de pájaro del hemisferio norte tiene un pico con sus mandíbulas cruzadas hacia la derecha o hacia la izquierda, lo que le permite abrir las piñas de las coníferas y alimentarse de las semillas. Pero no se observa ningún ave de la especie con el pico sin cruzamiento de las mandíbulas. ¿Qué tipo de selección natural ocurre?

links? do you have a link? i don't see anything?

some inherited genetic mutations can be good for the offspring, so the answer is different genetic mutations cause many forms of cancer.

bacteria could be both, harmful and to us. harmful bacteria could make us sick and probably even by getting the chances of getting a disease, but good bacteria fight it off with your immune system. there is always bacteria everywhere we go. we need to make sure to wash our hands after using the restroom, before eating, after eating, after petting an animal too. so you see, bacteria is everywhere and is harmful or . i hope this . : ) : ) : )