In order for natural selection to occur, charles darwin stated we must begin with a population of organisms that has genetic
a) competition.
b) engineering.
c) reproduction.
d) variation.

Two red blood cells each have a mass of 9.0 multiply.gif 10-14 kg and carry a negative charge spread uniformly over their surfaces. the repulsion arising from the excess charge prevents the cells from clumping together. one cell carries −2.50 pc of charge and the other −3.10 pc, and each cell can be modeled as a sphere 7.5 μm in diameter. (a) what speed would they need when very far away from each other to get close enough to just touch? assume that there is no viscous drag from any of the surrounding liquid. answer is: 321 m/s how do i find this (b) what is the maximum acceleration of the cells in part (a)? answer is: 1.38e+10 m/s2 how did they find this answer

En un laboratorio, nakisha mezcla una solución de hidróxido de sodio con un indicador llamado fenolftaleína. cuando se combinan, crean una solución de color rosa. nakisha se pregunta si la mezcla de otras soluciones con fenolftaleína también creará este color rosa. ? cómo podría nakisha utilizar el proceso de investigación científica para determinar si la mezcla de otras soluciones con fenolftaleína también creará un color rosa? marque las que correspondan.

Emagnitude of the electrical force acting between a +2.4 ×  10–8  c charge and a +1.8 ×  10–6  c charge that are separated by 0.008 m is    n, rounded to the tenths place.