The alveoli are lined with mucus and are surrounded by a network of blood capillaries. They have very thin walls for gases to be absorbed through. An individual air sac is called an alveolus. The layer of moisture in the alveoli allows gases to dissolve so that they can diffuse quickly.
So sound travels 1 kilometer in roughly 3 seconds and 1 mile in roughly 5 seconds. When you see the flash of a lightning bolt, you can start counting seconds and then divide to see how far away the lightning struck.
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.
Answer:
D. A bicycle rusting.
Explanation:
A. is incorrect because tearing a piece of paper is a physical change, not a chemical change.
B. is incorrect because we are just heating up the object. That only changes how fast the particles are moving and the change in state of matter.
C. is incorrect because we are adding heat to change a state of matter (from solid to liquid) and it is a physical change.
Therefore, only D. is the correct answer. Iron rusts, and when it does, it chemically changes into an iron oxide (rust).
Answer: parasitism
Explanation: Because it's relationship between two species of plants or animals in which one benefits at the expense of the other, sometimes without killing the host organism.