Some friends are trying to make wine in their basement. they've added yeast to a sweet grape juice mixture and have allowed the yeast to grow. after several days, they find that sugar levels in the grape juice have dropped, but there's no alcohol in the mixture. the most likely explanation is that
a. the mixture needs more sugar; yeast need a lot of energy before they can begin to produce alcohol the mixture needs less oxygen;
b. yeast only produce alcohol in the absence of oxygen the mixture needs more oxygen;
c. yeast need oxygen to break down sugar to produce alcohol the mixture needs less sugar;
d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.

The correct answer is d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.

Explanation:

As they added sweet grape juice mixture the amount of sugar increased in the content and it is seen that more than 6 % of sugar decreases the rate of fermentation and alcohol concentration also decreases and a moderate amount of glucose concentration in the anaerobic environment increases the fermentation results in more alcohol production.

High sugar concentration decreases fermentation but increases cellular respiration in the yeast, as a result, it uses more sugar for its growth and produce CO₂ and H₂O so alcohol is not the by-product of cellular respiration. Therefore the correct answer is d. high sugar concentrations stimulate cellular respiration, and alcohol is not a by-product of cellular respiration.

synovial joints are characterized by the presence of a joint cavity. the walls of this space are formed by the articular capsule, a fibrous connective tissue structure that is attached to each bone just outside the area of the bone’s articulating surface. the bones of the joint articulate with each other within the joint cavity.

friction between the bones at a synovial joint is prevented by the presence of the articular cartilage, a thin layer of hyaline cartilage that covers the entire articulating surface of each bone. however, unlike at a cartilaginous joint, the articular cartilages of each bone are not continuous with each other. instead, the articular cartilage acts like a teflon® coating over the bone surface, allowing the articulating bones to move smoothly against each other without damaging the underlying bone tissue. lining the inner surface of the articular capsule is a thin synovial membrane. the cells of this membrane secrete synovial fluid (synovia = “a thick fluid”), a thick, slimy fluid that provides lubrication to further reduce friction between the bones of the joint. this fluid also provides nourishment to the articular cartilage, which does not contain blood vessels. the ability of the bones to move smoothly against each other within the joint cavity, and the freedom of joint movement this provides, means that each synovial joint is functionally classified as a diarthrosis.

outside of their articulating surfaces, the bones are connected together by ligaments, which are strong bands of fibrous connective tissue. these strengthen and support the joint by anchoring the bones together and preventing their separation. ligaments allow for normal movements at a joint, but limit the range of these motions, thus preventing excessive or abnormal joint movements. ligaments are classified based on their relationship to the fibrous articular capsule. an extrinsic ligament is located outside of the articular capsule, an intrinsic ligament is fused to or incorporated into the wall of the articular capsule, and an intracapsular ligament is located inside of the articular capsule.

at many synovial joints, additional support is provided by the muscles and their tendons that act across the joint. a tendon is the dense connective tissue structure that attaches a muscle to bone. as forces acting on a joint increase, the body will automatically increase the overall strength of contraction of the muscles crossing that joint, thus allowing the muscle and its tendon to serve as a “dynamic ligament” to resist forces and support the joint. this type of indirect support by muscles is very important at the shoulder joint, for example, where the ligaments are relatively weak.

additional structures associated with synovial joints

a few synovial joints of the body have a fibrocartilage structure located between the articulating bones. this is called an articular disc, which is generally small and oval-shaped, or a meniscus, which is larger and c-shaped. these structures can serve several functions, depending on the specific joint. in some places, an articular disc may act to strongly unite the bones of the joint to each other. examples of this include the articular discs found at the sternoclavicular joint or between the distal ends of the radius and ulna bones. at other synovial joints, the disc can provide shock absorption and cushioning between the bones, which is the function of each meniscus within the knee joint. finally, an articular disc can serve to smooth the movements between the articulating bones, as seen at the temporomandibular joint. some synovial joints also have a fat pad, which can serve as a cushion between the bones.

im not intirely sure but i think the anwser is d relative humidity