Answer:
D. Yes, two hydrogen bonds could form between thymine and cytosine.
Explanation:
A hydrogen bond (often informally abbreviated H -bond) is a primarily electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative atom or group, particularly the second-row elements nitrogen (N), oxygen (O), or fluorine (F)—the hydrogen bond donor (Dn)—and another electronegative atom bearing a lone pair of electrons—the hydrogen bond acceptor (Ac).
The formation of stable hydrogen bonds depends on the distance between two strands, the size of the bases and geometry of each base. Stable pairings occur between guanine and cytosine and between adenine and thymine (or adenine and uracil in RNA).
One hydrogen bond could form between the C4 carbonyl group on thymine (a hydrogen bond acceptor) and the C4 amino group on cytosine (a hydrogen bond donor). Another hydrogen bond could form between N3 of thymine (a hydrogen bond donor) and the N3 of cytosine (a hydrogen bond acceptor). Note that the C2 carbonyl groups found on both bases are both hydrogen bond acceptors and therefore a hydrogen bond cannot be formed between them.
Answer:The urinary system, also known as the renal system, produces, stores and eliminates urine, the fluid waste excreted by the kidneys. The kidneys make urine by filtering wastes and extra water from blood. Urine travels from the kidneys through two thin tubes called ureters and fills the bladder. When the bladder is full, a person urinates through the urethra to eliminate the waste.
The urinary system is susceptible to a variety of infections and other problems, including blockages and injuries. These can be treated by a urologist or another health care professional who specializes in the renal system
Explanation:
Increased pressure to eat healthy and cut down portion sizes
Reduced pressure to exercise regularly within the target heart rate zone
A. True
The space used to grow food to feed cattle and other kinds of livestock could easily feed the entire world if put to use growing the humans food.
