145 hours.
Explanation: Riding a bicycle for one hour expends 505 kcal of energy. Given that one gram of body fat equals 7.70 kcal, and 1 pound of body fat is equivalent to 454 grams:
1 lb = 454 g; thus, 21 lb = 21 × 454/1 = 9534 g. Moreover, converting 9534 g of body fat gives us 9534 × 7.70 kcal/1 = 73411.8 kcal. If riding for one hour burns 505 kcal, then to lose 73411.8 kcal, it would require 73411.8 kcal x 1 hour/505 kcal = 145 hours.
An r-selected species has a significantly faster reproductive rate compared to K-selected species.
The focus of r-selected species is on quick maturation and reproduction. They are likely to breed during short periods when water supply is available, thus enhancing their survival chances.
Conversely, K-selected species prioritize nurturing their young and tend to reproduce later. Due to the longer maturation time before breeding, by the time K-selected species are ready, the water supply may be depleted, leading to lower survival odds.
Hope this clarifies!
If you have more questions, don’t hesitate to ask! Have a fantastic day!:)
~Collinjun0827, Junior Moderator
Hello!
density = 2.67 g/cm³
volume = 30.5 mL
Thus:
Mass = density * volume
Mass = 2.67 * 30.5
Mass = 81.435 g
Solution:
Washing Clothes & Dissolving Sugar
Clarification:
Consider each scenario:
1) For washing clothes, water is essential; without it, washing is ineffective.
2) Connecting brake pedals to brake pads requires solids, not liquids.
3) To deodorize a space, one would likely reach for an aerosol spray, which is a gas.
4) Sculpting involves solid tools and a solid medium.
5) Dissolving sugar necessitates a liquid to be effective!
6) While one might assert that paint is a liquid, it still might not fit the category; I would categorize this application as solid.
7) Gears employed in machinery are solid components!
A indicates the power lines are what truly conducts (or transmits) the power.
Options B or E are incorrect, as wood is not a good conductor. That's why it's commonly used in homes to retain heat (which comes from electricity), preventing it from escaping.
Option C is also not correct since rubber, similarly, is a poor conductor. Like wood, it acts as an insulator, not transmitting heat (or electricity). This is why rubber gloves are utilized during electrical work.
Option D is valid—most metals are excellent electricity conductors. For instance, copper pans are efficient in cooking because copper effectively conducts heat. Being a metal, this is also why wire cutters have rubber grips; it isolates the user from potential electric shock from the conductive metal. The rubber serves as a barrier to protect against electrocution when handling wires or electricity.
