What type(s) of matter do light waves travel best in?

Which of the following is a common response to cell signaling?

What are the two causes of density in deep current waters? a. salinity (how much salt) of the water and high temperaturesb. salinity (how much salt) of the water and low temperatures c. oxygen content of the water and high temperatures. d. oxygen content of the water and low temperatures

Black fur(b) in guinea pigs is dominant over white fur(b). find the probability of a homozygous offspring in a cross: bb x bb. a. 0% b. 25% c. 50% d. 75% e. 100%