Answer: Option A
Explanation:
A tunicate is marine invertebrate animal which is a part of chordates. They have notochords and dorsal nerve chord. The subphylum of the organism is called as Urochordata.
The adult urochordates lack notochord but the larval stage of the urochordates have notochord. This is because it helps in swimming of the organism which is required only at the larval stage.
The adult stage of the tunicates is sessile and they do not swim so they do not require notochord.
Answer:
B) Nitrogen-fixing bacteria and lightning
Explanation:
Nitrogen cycle is the natural process in which atmospheric nitrogen is converted into nitrite and nitrate with the help of bacteria.
Nitrogen cycle is directly dependent on nitrogen-fixing bacteria and lightning.
As bacteria are responsible for most of the chemical conversion in the nitrogen cycle such as nitrogen fixation (first step) is done by soil bacteria (Cyanobacteria) that form ammonia, which is toxic to plants; nitrification in which ammonia is converted into nitrites and nitrates with the help of Nitrobacter and denitrification bacteria involve Pseudomonas, and Achromobacter which convert nitrite and nitrate into nitrogen.
The lightning breaks nitrogen molecules and allow it to combine with oxygen in atmosphere which further dissolve in rain and form nitrates.
Hence, the nitrogen cycle is most directly dependent upon nitrogen-fixing bacteria and lightning and the correct option is B.
When your body temperature is too high your blood vessels will dilate then your sweat glands secrete fluid and the heat is lost from the body.. there for without sweat you would “heat to death”
Answer:
No
Explanation:
Atmospheric refraction raises the sun about 1/2 degrees upward in our sky at both sunrise and sunset. This advances the time of actual sunrise, while delaying the time of actual sunset. This gives several minutes of extra daylight, not just at an equinox.
Answer:
Reflexes are not a function of the spinal cord.
Explanation:
The spinal cord is part of the central nervous system and is made up of neurons that go along it (from the end of the brain stem almost to the bottom of the spine).
The spinal cord receives incoming messages from the peripheral nervous system (including the sensory neurons) and pass on messages from the brain to efferent neurons (motor neurons at muscles).
The spinal cord contributes to learning as it passes on the info received from sensory neurons (that there is an obstacle in the path) to the brain and passes on the response from the brain to the muscles (to lift the foot up higher).
The spinal cord is essential for integration as it passes on sensory information to the brain to determine motor output.
Reflexes are when sensory information is quickly sent straight to motor neurons to move. It does not need to go to the brain (hence does not need to go to the spinal cord) for the reaction as it would be too slow. This is seen when someone who is paraplegic (paralysed at lower torso) can still move their leg in response to the doctor tapping their knee even when they cannot forcibly move their legs.
Therefore reflexes are not a function of the spinal cord.
