Answer:
There are a great many feeding relationships in any ecosystem, but energy always flows from primary producers to various consumers. These feeding relationships are represented by food chains and food webs. A food chain is a sequence in which organisms transfer energy by eating and being eaten.
Explanation:
Using ideal gas equation, PV = nRT, and since there is no volume change and amount change, the equation is now P = kT, where k =nR/V. Temperature must be in kelvin
From the given, k = (0.82)/ (21 + 273) = 2.78 x 10^-3
Substituting T = -3.5+273, P = 0.75 atm
There are 195 countries in the world today. This total comprises 193 countries that are member states of the United Nations and 2 countries that are non-member observer states: the Holy See and the State of Palestine.
There are 50 US states.
The United States currently administers 16 territories as insular areas:
American Samoa.
Guam.
Northern Mariana Islands.
Puerto Rico.
U.S. Virgin Islands.
This information is from three sources. United Nations, Wikipedia, and United States and their satellite states aka countries.
Hey There!:
The density is the quotient between the mass of a material and the volume occupied by it, The density can be expressed for a substance or for a mixture of substances. For example, water density in ambient conditions is equal to 1.00 g/cm3, which means that in 1 cm³ or 1 mL, there are 1.0 g of water. Therefore:
D = m / V
D = 20 g / 5 mL
D = 4,0 g/mL
hope that helps!