Answer:
"Option B. The tilt of the moon´s orbit around the earth
" limits the number of eclipses per year
<u>Explanation</u>:
The moon's orbit is tilted only by 
. Around the sun when the earth and moon move, the tilt of the moon changes according to the direction of the sun. When the same thing occurs to the earth, the seasonal changes occur. The theory is all related to moon's formation. Due to this tilt the moon's road near the stars changes slightly in every month. The inclination is with respect to the ecliptic plane. If this inclination was absent then we could have felt the eclipse more frequently.
Explanation:
charles darwin proposed thoery of natural selection.he had collected imnumerable specimens of plant and animals.he published concept survival of fittest. while explaining he says that There is always competition for food.only those organism survive which shows adptations in various reasons. it thoery of natural selection.
There are some objections,
1. natural selection is not only factor responsible for evolution.
2. darwin did not mention uesful and useless modifications.
3. There is no explanation about slow and abrupt changes
Answer:
b) to deliver nutrients and other essential materials to cells
If the paramecium was not able to contract its contractile vacuole, it would be in danger of bursting. The cell would not be able to hold too much water. This would happen faster if the paramecium was in water with a low salt concentration because there is more water and less salt, so the water would accumulate faster.
