(Q).
Answer the following question given this paragraph: Like mitochondria, plastids contain their own DNA. Therefore, according to endosymbiotic theory, plastids may also have evolved from ancient, free-living prokaryotes that invaded larger prokaryotic cells. If so, they allowed early eukaryotes to make food and produce oxygen. Q: Like mitochondria, plastids contain their own what? Choices: - riboflavin - bacteria - molecule - dna A:
(A).
dna

(Q).
Answer the following question given this paragraph: Deformation of the ionic crystal causes one plane of atoms to slide along another. The resulting repulsive interactions between ions with like charges cause the layers to separate. Crystals tend to have relatively sharp, well-defined melting points because all the component atoms, molecules, or ions are the same distance from the same number and type of neighbors; that is, the regularity of the crystalline lattice creates local environments that are the same. Thus the intermolecular forces holding the solid together are uniform, and the same amount of thermal energy is needed to break every interaction simultaneously. Amorphous solids have two characteristic properties. When cleaved or broken, they produce fragments with irregular, often curved surfaces; and they have poorly defined patterns when exposed to x-rays because their components are not arranged in a regular array. An amorphous, translucent solid is called a glass. Almost any substance can solidify. Q: Why do crystals have relatively sharp and well-defined melting points? Choices: - particular intermolecular forces - variable intermolecular forces - angular intermolecular forces - uniform intermolecular forces A:
(A).
uniform intermolecular forces

(Q).
Answer the following question given this paragraph: When a series of straight waves strike an impenetrable barrier, the waves stop at the barrier. However, the last particle of the medium at the back corner of the barrier will create circular waves from that point, called the point source. This can be seen in the image below. This phenomenon is called diffraction , and it occurs in liquid, sound, and light waves. While the waves become circular waves at the point source, they continue as straight waves where the barrier does not interfere with the waves. Q: What is the phenomenon in which light and sound waves become circular at the point source of a barrier? Choices: - refraction - sonic wave - reflection - diffraction A:
(A).
diffraction