Independent: The second group is not given the drug.
Dependent: Dr. Smith wants to examine weather a new drug increases the maze running performance of older rats.
Constants: Dr. Smith teaches two groups of older rats to find a piece of tasty rat chow in the maze.
Answer:
Option-D
Explanation:
Casparian strips are the strips or band composed of a hydrophobic substance called the suberin which forms the ring-like structure in the endodermis of the vascular plants.
The Casparian strips are present around the vascular bundles in the endodermis to allow the uptake of the selective nutrients as the substance has to pass through the cell membrane before it enters the centre of the root or stele or vascular bundles.
The Casparian strips allow the movement of a substance through symplast mode only, therefore, is ensures the substance to pass through the cell membrane.
Thus, Option-D is correct.
Answer:
With sufficient stimulation, mature sperm travel from the epididymis through the vas deferens, a muscular tube, which propels sperm forward ...
Explanation:
Answer and Explanation:
Fossils can be formed in a variety of ways. First and foremost, organisms that possess bones (or shells) are the best candidates for fossilization because these structures commonly remain in fossilizing substances such as mud.
The most preserved fossils come from animals that die in aquatic environments or in environments that have a high level of humidity. This occurs because the animal gets buried in a sediment like mud, leading to the decomposition of soft structures and the fossilization of hard structures, such as bones. As layers of sediment are added, the dead body of the organism becomes a fossil.
Also, animals can leave well-preserved fossils during volcanic eruptions when they get trapped in hot ash flows. In addition, this could also occur in tundra ecosystems when animals get trapped in ice, leaving a well-preserved fossil inside. Moreover, plants are also fossilized, this generally takes place in sediments such as coal.
Finally, paleontologists are able to find the fossils once they become exposed thanks to a process called erosion.