Answer:
The human mitochondrial DNA (mtDNA) is a double-stranded, circular molecule of 16 569 bp and contains 37 genes coding for two rRNAs, 22 tRNAs and 13 polypeptides. The mtDNA-encoded polypeptides are all subunits of enzyme complexes of the oxidative phosphorylation system.
Explanation:
<span>In the question,'when a doctor is able to determine the sex of the foetus, during an ultrasound scan, what stage of development is the foetus in, the correction option is D, that is, the second trimester. Human pregnancy usually lasts for an average of nine months. The nine months are divided into three parts of three months each called trimester. The first trimester is made up of the first week of the pregnancy to the twelfth week. During this period, the foetus is just developing and can not be picked up easily by an ultrasound scan, but by the second trimester, which is week thirteen to week twenty four, the foetus would have develop enough to be picked up by the ultrasound scan. At this stage, the doctor can easily determine the sex of the foetus whether it is a boy or a girl.</span>
Answer:
Cancer
Explanation:
In all types of cancer, some of the body´s cells begin to divide without stopping and spread into surrounding tissues.
When cancer develops, the cells become more and more abnormal, old aor damaged cells survive when they should die, and new cells form when they are not needed. These extra cells can divide without stipping and may form growths called tumors
Answer:
The correct option is this: GRASS GROW ON A SAND DUNE, IS REPLACED BY SHRUBS AND THEN BY TREES.
Explanation:
Ecological succession refers to the gradual process by which the living organisms in a particular environment are replace overtime. Succession usually occurs as a result of disturbance to the original environment. Ecological succession can be termed as primary or secondary succession based on the type of environment in which the succession occur. One unique features of ecological succession is that lower living organisms are usually replaced with advanced living organisms as time goes on. For instance, in option D, the grasses were replaced by shrubs, which are also later replaced by trees.