Answer:
The endosymbiotic theory explains the origins of eukaryotic cells.
Explanation:
In the atmosphere, the density of air particles decreases with height, with more gas particles remaining near the surface of Earth. When only taking into account humidity, dry air is more dense than moist air because of molecular weights of the gases.
Answer:
The correct answer is- Histone
Explanation:
DNA is approximately 2.2 m long thread which has to be adjusted in a microscopic nucleus so DNA must be in a supercoiled form to be present in the nucleus and this supercoiling of DNA is done on histone protein.
Histone protein is a positively charged protein that is made up of eight proteins so it is called histone octamer. Each histone has 2 copies of each protein that is H2A, H2B, H3, and H4.
DNA is negatively charged and histone protein is positively charged therefore DNA wraps around histone protein which causes the packaging of DNA. So the correct answer is histone protein.
Answer
At week 5-6 of gestation, the baby’s heart starts beating.
Explanation
Fertilization occurs in week 3 followed by implantation in week 4.In week 5 the levels of hormones increases with formation of the baby’s heart and circulation system. In week 6, the neutral tube closes followed by development of structures necessary to form eyes and ears. The head of the baby develops at week 7 followed by nose in week 8 and toes in week 9.