What must be true about the population in order for evolution by natural selection to take place? The population must have a large number of individuals that can reproduce and produce fertile offspring.

The population must have genetic variation that leads to differential survival and reproduction.

The population must have strong individuals capable of fighting off other populations when threatened.

The population must have well camouflaged individuals to avoid being eaten by predators.

After reading the paragraph below, answer the questions that follow. researchers have created a robot that has a very thin leg that is moved by cardiac (heart) cells contracting in unison. the robot, made of a polymer similar to that used in making contact lenses, is bathed in heart cells with supporting cells, which then attach to the robot and provide movement as they contract. all of the cardiac cells working together can cause the robot leg to move in a way that individual cells could not. this is an example of a. emergent properties of cells. b. energy flow through an ecosystem. c. adaptation. d. internal environment regulation.

Johnny rode his bike to a friend's house 4 blocks down the street in his neighborhood. he immediately rode back home once he realized his friend was not able to play. what was his displacement for the total bike ride? how did you determine this? what could we use as a reference point to determine he was in motion during his bike ride? why can you use it as a reference point

Give three examples of plant activities that are affected by circadian rhythms and natural fluctuations in the length of daylight?