Jenny plucked a tight string softly, then harder. What happened when Jenny plucked the string harder?

Triss [41]

Density is a derived unit because it's not reported as a pure unit. (A pure unit would be something like kilograms or meters.) In contrast, the units for density are kg/m3. Density is the ratio of mass to volume; mass has the unit 'kilograms' (kg) and the unit for volume is cubic meters (m3).

Density is an intensive property, which means the amount of the material is irrelevant. The density of a substance is constant.

4 0

4 years ago

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Which of the following best explains how hydrogen bonding aftects the heat of vaporization for water?

dlinn [17]

Answer: A. The hydrogen bonds cause water to resist a change in temperature.

Explanation:

Heat of vaporization is defined as the amount of heat required to convert 1 mole of liquid to gaseous state.

Water has high heat of vaporization due to the presence of strong hydrogen bonds between hydrogen and a electronegative element oxygen. As the water molecules are strongly bonded to each other, large amount of heat is required to raise the temperature of water.

The molecules will not be able to gain enough kinetic energy and thus temperature changes slowly.

5 0

3 years ago

Give me another real-life example for each type of symbiotic relationship<br>

olga55 [171]

Answer:

Mutualism: both partners benefit. An example of mutualism is the relationship between the Egyptian plover and the crocodile. In the tropical regions of Africa, the crocodile lies with its mouth open. The plover flies into its mouth and feeds on bits of decaying meat stuck in the crocodile’s teeth. The crocodile does not eat the plover. Instead, he appreciates the dental work. The plover eats a meal and the crocodile gets his teeth cleaned. Coincidentally, the Egyptian plover is also known as the crocodile bird.

Commensalism: only one species benefits while the other is neither helped nor harmed. For example, remora fish are very bony and have a dorsal fin (the fin on the back of fish) that acts like a suction cup. Remora fish use this fin to attach themselves to whales, sharks, or rays and eat the scraps their hosts leave behind. The remora fish gets a meal, while its host gets nothing. Selfish, sure, but neither gets hurt.

Parasitism: One organism (the parasite) gains, while the other (the host) suffers. The deer tick is a parasite. It attaches to a warmblooded animal and feeds on its blood. Ticks need blood at every stage of their life cycle. They also carry Lyme disease, an illness that can cause joint damage, heart complications, and kidney problems. The tick benefits from eating the animal's blood. Unfortunately, the animal suffers from the loss of blood and nutrients and may get sick.

Explanation:

3 0

3 years ago

Which of the following best explains why a cell spends most of the time during the cell cycle in interphase?

worty [1.4K]

Answer:

c) growth of the cell and replication of DNA prepare the cell for division

4 0

4 years ago

Match the prokaryotic cell structures to the characteristic of life.

djverab [1.8K]

Answer:

1. Nucleoid: Prokaryotes do not have well defined nucleus. Instead, naked DNA or genetic material is found in the these cells which keeps floating freely in the region of cytoplasm called as mucleoid (nucleus-like). DNA carries the genetic information required for growth, development, metabolic activities and reproduction.

Hence, it must match with b. reproduction: DNA ensures that future generations will be similar to parents

2. Cell wall: Cell wall is the outermost layer surrounding the plasma membrane. It is composed of polysaccharides and is found in bacteria, fungi, and plant cells. In bacteria, it is generally composed of peptidoglycans. Antibiotic such as penicillin acts on the cell wall and creates pores in it which kills the bacteria.

Hence, it can be correctly matched with d. homeostasis: taking an antibiotic, such as penicillin, creates holes in the cell wall of some bacteria, so they lose water and die

3. Flagellum: It is a thread or hair like structure which serves the purpose of locomotion in the cells specially in bacteria, protozoa, spermatozoa etc. In bacteria, it helps in moving in the direction of food and moving away from inhospitable environment.

Hence, it can be correctly matched with e. responding to stimuli: move away from a less hospitable environment or towards a more hospitable environment.

4. Pilus: It is a hair like but rigid structure that protrude from the cell surface of the bacteria. It helps in the process of conjugation by forming a conncetion between cell surface of two bacteria.

Hence, it can be correctly matched with a. reproduction: exchanging genetic material in process of conjugation

5. Ribosomes: Ribosomes serve as the site of protein synthesis in the cell. Bacterial ribosomes are composed of two sub-units with sedimentary constant of 50S and 30S.

Hence, it can be correctly matched with c. maintaining homeostasis: protein is needed for enzymes and repairing structures

6. Cytoplasm: It is gel like material found within the cell (excluding nucleus in case of eukaryotes). All the metabolic activities of the cell generally take place in the cytoplasm of the cell.

Hence, it can be correctly matched with f. homeostasis: using energy, all chemical reactions are performed in the cytoplasm

4 0

3 years ago