Answer:
Option c (No, T cells left from the previous infection can kill any virus.
)
Explanation:
When ever viral infection occur, body's immune system start to fight against it by activating B-cells and T-cells.
B-cells produce antibodies that bind with virus and act as label. This label indicate virus as foreign substance. Hence T-cells recognize it and kill it. Furthermore, B-cells form memory cell that keep the viral memory. if this viral infection occur again in future, T-cell recognize it and eliminate the virus.This mechanism is called immunity.
Answer:
The process of making food by the green plant by using sunlight,water,mineral, carbon dioxide,etc.is called photosynthesis.
hope this not childish.
Answer:
Option B
Explanation:
Both the US industrialist John D. Rockefeller and Andrew Carnegie believed that the law of nature govern even the industrial , business or corporate sector. As in a wild forest, strongest animal survives by feeding the weak animals, like wise the business/industries/corporation of large size survive by feeding or eliminating the smaller ones. They think that this is not at all evil but it is as per the law of nature.
Thus, option B is correct.
5 desert animals are camel, sand cat, desert tortoises, desert lizards and the great road runner.
<u>Explanation:</u>
- Camel has several physiological and behavioral adaptations that help them survive the extreme conditions of the desert. They have flat feet to help them spread their weight in the sand.
- They have thick eyelashes and closeable nostrils to prevent the entry of sand. They store fat on their humps that supplies energy during long journeys and has a long large intestine which increases water reabsorption.
- Sand cat is similar to the domestic cat in basic appearance but has several adaptations enabling it to survive in the desert. Their paws are covered with thick and long hairs to protect the feet from the heat. They have thick fur that acts as an insulting surface during hot days and cold nights.
- Desert tortoises have excellent water storage capacity. Their bladders are larger than normal and can carry extra water. They have strong feet which helps them to dig holes in the sand and access rainwater.
- Desert lizards can drink water through skin. They do it by a process called cutaneous water acquisition and it helps them to gather water obtained from rainfall, damp sand and pools.
- Great roadrunner has peculiar adaptations. The digestive system of the bird retrieves water from the feces as it is in the excretory canal.
