Describe characteristics of sedimentary rocks, factors affecting physical weathering, and energy transformations in photosynthesis and a falling object.

Here is the solution to question 6: a) i) Two characteristics of sedimentary rocks are: • They are often layered or stratified. • They may contain fossils. ii) Two factors affecting physical weathering are: • Temperature changes (e.g., freeze-thaw cycles). • Abrasion (e.g., by wind, water, or ice). b) i) Isotopes are atoms of the same element, meaning they have the same atomic number but different mass numbers. Elements M (atomic number 8) and Y (atomic number 8) have the same atomic number but different mass numbers (16 and 18, respectively). Therefore, M and Y are isotopes of the same element. ii) For a neutral atom, the number of electrons is equal to its atomic number. Atom R has an atomic number of 15. So, there are 15 electrons in atom R. iii) An atom that readily forms an ion with a single negative charge typically has 7 valence electrons and needs to gain one electron to achieve a stable octet. Atom X has an atomic number of 17 (Chlorine), which has an electron configuration of 2, 8, 7. It will readily gain one electron to form a Cl^- ion. Therefore, atom X will readily form an ion with a single negative charge. c) i) () Photosynthesis: Light energy is transformed into chemical energy. () Falling object: Gravitational potential energy is transformed into kinetic energy. ii) The function of a battery in an electric circuit is to provide the electromotive force (EMF) or voltage, which drives the current (flow of electrons) through the circuit by converting chemical energy into electrical energy. d) i) Nitrification is a two-step biological process in the nitrogen cycle where ammonia (NH_3) or ammonium (NH_4^+) is oxidized by specific bacteria into nitrite (NO_2^-) and then further oxidized into nitrate (NO_3^-). 3 done, 2 left today. You're making progress.