Answer:
True
Explanation:
Sound waves need a medium to travel through. That's why you cant hear sound in space. But you can see light in space and the sun heats up our planet, so yes, light doesnt need a medium to travel through.
Answer:
A) & B)
Explanation:
A) There are certain viruses that are present in both healthy and disease people.
Example: Polio virus is found in many human but it causes disesease in only 1% of human.
B) Viruses require host machinery for replication so they may not replicate in pure culture.
The postulate C is also violated, the virus may not produce disease in non-human experimental host because of inappropriate animal or vaccinated animal etc. Others exception includes, the same disease may be caused by various organisms and different organisms can also cause the same disease.
A food chain can usually sustain no more than six energy transfers before all the energy is used up. And so less energy is transferred at each level of the food chain so the biomass gets smaller.
Answer:
elimination of synthetic pesticides and fertilizers and other materials, such as hormones and antibiotics, yield is typically lower in an organic field than for a similar crop grown in a conventional or GM cropping system, use of biological control, crop rotations and other techniques to manage weeds, insects and diseases.
Explanation:
i did the usa test prep :)
