Why is it necessary to add a day to the calendar every four years? A. The rotation of the Earth is actually 24 hours and 6 seconds.
B. The revolution of the Earth is actually 365.25 days not 365 days.
C. The Earth's orbit is elliptical and not circular.
D. The Earth's axis is tilted and slows its rotation.

Imagine ? person stepping on a pin and pulling his or her foot way look at the réfléchir arc of the scenarios below

If the coding part of an mrna molecule is 1800 nucleotides (bases) in length, this molecule will contain codons and code for a polypeptide that is amino acids long.

Elephants in the savanna regions of africa dig holes in dried up river beds to reach water lying just below the surface. these holes provide drinking water for other animals as well. so, without the elephants, many animals might otherwise die from lack of water during the dry season. the location in which the elephants live is an example of a/n and the role they play in creating water holes is an example of a a) ecosystem; habitat b) community; niche c) habitat; niche d) niche; habitat