Alveolar walls are thin to enable the quick passage of oxygen in and out of the lungs. The lungs works hand-in-hand with the heart and also is responsible in converting blood that's de-oxygenated into an oxygenated blood that is usable by the organ systems of the body. The alveolar walls are also designed to have thin membranes so that it can expand and constrict quickly allowing us to breather properly.
I only have an answer for number 24, I'm sorry! But one piece of evidence is the DNA sequences, they have discovered that humans and monkeys/apes share a common ancestor through DNA. Another would be fossils, scientists have fossils to show great similarities in the skull and jaw structure, along with the legs, comparing to humans.
The four main stages of Interphase are Gap 0, Gap 1, S phase and Gap 2. Interphase appears to be a resting stage in cell divisions but actually many activities or processes happens at this phase. Interphase generally lasts at least 12 to 24 hours in mammalian tissue.
