Answer:
The correct answer is option (D) there was a time in Pennsylvania history when dinosaur existed.
Explanation: A paleontologist discovers a rock slab on which the footprints of a Pennsylvania dinosaur are well preserved. This means that there was a time in Pennsylvania history when dinosaur existed in this area. Here fossil is a fragment of rock on which the footprints of dinosaur is present.
Answer:
Menstruation, the follicular phase, ovulation and the luteal phase.
Explanation:
Menstruation, the follicular phase, ovulation and the luteal phase are the four events or phases of the menstrual cycle. Luteinizing hormone, follicle-stimulating hormone, and the female sex hormones i.e. estrogen and progesterone are the types of hormones that controls the uterine cycle. Each event in the uterine cycle has its own significance in the female body.
The vector, which is often a small, circular piece of dna that can exist outside the bacterial chromosome, is known as a plasmid.
Bacteria and certain other microscopic species contain plasmids, which are tiny circular DNA molecules. Physically distinct from chromosomal DNA, plasmids multiply on their own. They normally contain only a few genes, including some linked to antibiotic resistance, and they can spread from one cell to another.
Recombinant DNA techniques are used by scientists to splice the genes they want to research into a plasmid. The inserted gene is duplicated along with the plasmid when it duplicates itself. Molecular cloning, the process of creating DNA molecules and introducing them into a host cell, uses plasmid vectors as the means of delivering recombinant DNA into the host cell.
To know more about plasmids, refer to the following link:
brainly.com/question/7826558
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- To keep our oxygenated blood and our deoxygenated blood separate.
Having 4 chambers allows these 2 types of blood to reach their appropriate destination without getting mixed up.
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