Open Ended Infer why there are virtually no freshwater echinoderms

Introductory Chemistry 5
Classify each substance as a pure substance or a mixture. If it is a pure substance, classify it as an element or a compound. If it is a mixture, classify it as homogeneous or heterogeneous. (a) helium gas (b) clean air (c) rocky road ice cream (d) concrete

Introductory Chemistry 5
Write balanced complete ionic and net ionic equations for each reaction. (a) \(\mathrm{AgNO}_{3}(a q)+\mathrm{KCl}(a q) \rightarrow \mathrm{AgCl}(s)+\mathrm{KNO}_{3}(a q)\) (b) \(\mathrm{CaS}(a q)+\mathrm{CuCl}_{2}(a q) \rightarrow \mathrm{CuS}(s)+\mathrm{CaCl}_{2}(a q)\) (c) \(\mathrm{Na

Principles of General Chemistry 2
Problem 65P Disulfur decafluoride is intermediate in reactivity between SF4 and SF6. It disproportionates at 150C to these monosulfur fluorides. Write a balanced equation for this reaction, and give the oxidation state of S in each compound.

Earth Science 13
Briefly describe the concept of elastic rebound. Develop an analogy other than a rubber band to illustrate this concept.

Organic Chemistry 9
Show how you would convert 2-methylcyclopentanol to the following products. Any of these products may be used as the reactant in any subsequent part of this problem. (a) 1-methylcyclopentene (b) 2-methylcyclopentyl tosylate (c) 2-methylcyclopentanone (d) 1-methylcyclopentanol (e) 1,2-dimethylcyclopen

Principles of Economics 6
Pharmaceutical drugs have an inelastic demand, and computers have an elastic demand. Suppose that technological advance doubles the supply of both products (that is, the quantity supplied at each price is twice what it was). a. What happens to the equilibrium price and quantity in each market? b. W

Concepts of Biology 1
What is the main difference between dispersal and vicariance? a. One leads to allopatric speciation, whereas the other leads to sympatric speciation. b. One involves the movement of the organism, whereas the other involves a change in the environment. c. One depends on a genetic mutation occurring, w

Biochemistry 9
Why is it essential that the mechanisms that activate glycogen synthesis also deactivate glycogen phosphorylase?