Will give brainliest

which statement is true?

spiral and elliptical galaxies have gas and dust between stars while irregular galaxies do not.
spiral and irregular galaxies have gas and dust between stars while elliptical galaxies do not.
irregular galaxies have gas and dust between stars while elliptical and spiral galaxies do not.
elliptical galaxies have gas and dust between stars while irregular and spiral galaxies do not.

4.06 hc)a five-year review of threats to the southern resident orca population of the united states concluded that the top threats were prey availability, contaminants, and effects from recreational and whale watching vessels. further down the list are oil spills, disease, and effects from commercial vessels not targeting whales. how might this list be different if it were for transient whale populations, which have a larger average population size and live farther offshore in open waters? a)the transient population is more likely to be affected by contaminants. b)the transient population is less likely to be affected by whale watching vessels. c)the transient population is more likely to be affected by disease. d)the transient population is less likely to be affected by prey availability.

Which of these substances does not protect against invaders in the nonspecific immune response? a. saliva b. mucus c. tears d. urine

Photosynthesis uses co2 and cellular respiration produces co2. we call the point when the two processes are in balance--when there is no net production of co2--the compensation point. how might you limit one of the processes in order to achieve a compensation point?