In most stable freshwater environments, populations of Daphnia are almost entirely female and reproduce asexually. However, male
s are observed in low oxygen environments or when food is scarce. Based on these observations, a researcher suggests that male Daphnia develop in response to unfavorable environmental conditions. This is an example of a:
generally considered to have originated in the late nineteenth century as a reaction to the abuses of big business and the problems that plagued the lower socio-economic classes of that era.
My guess would be an energy source, water, and an atmosphere.
Explanation:
Whatever lives there is going to need energy and water to survive. The atmospheric layer will protect the planet like ours protects Earth. Hope this helps! :)
The heart valves prevent blood from flowing in the wrong direction in the heart. The valves are held in the proper place because of the chordae tendinae.
