Option 1
Explanation:
Cirrus clouds are short, detached, hair-like clouds found at high altitudes
Answer:
I would write "terrestrial/lives on land during all life stages" between the frog and pigeon branches
Explanation:
Jaw evolution has started with fish, so i'd place that before the perch, evolution of four limbs is next and I would plate it between the perch and the frog. Evolution of an egg has ensured that organisms remain terrestrial during all stages of life and don't need to rely on water to lay their eggs. So I would place that between the frog and the pigeon. True mammary glands and true hair, as we know it formed on mammals so i'd place that between the pigeon and the rats (although synapsids evolved similar structures long before birds even existed). And lastly, I would place "walking on two legs" between rats and human branches. Because our ancestors evolved bipedalism relatively late.
The answer is 4.
Gases have low densities, because of the increased space between hight-energy particles.
