Answer:
because the ovum is made to fertilize only a sperm at a time, once a sperm enters it closes. It then divides to form twins, triplets and so on
Explanation:
Fossil fuels are important energy sources for our every day activities.
Formation of fossil fuels
Fossil fuels forms from the accumulation and burial of organisms in a basin of deposition. Instead of the organisms decaying, they preserve their carbon content. To be worthy of becoming fossil fuels, organisms must be buried in an environment where there is little to no oxygen to fast-track decomposition of the buried organic matter. Increase in temperature and pressure causes the organic matter to transform into fossil fuels.
How are they obtained
First, different fossil fuels have their extraction techniques because they occur in different physical state of matter.
For the solids e.g coal: exploration is carried out first and if a prospect is delineated, mining engineers design the best way to extract the coal from nature. Coal is usually found laid in sedimentary beds in nature. Top layers of sediments can be removed to extract the coal.
For fluids such as crude oil and natural gas, after a prospect is identified, a rig is usually constructed to extract the fluid and gas. The natural pressure allows for the fluids the rise within the drill used in extraction.
How are they used
Coal and gas are used to power electrical generating plants. They are used to heat steams which drives turbines and produce electricity.
Natural gas is used as a domestic fuel for cooking and so also coal.
When crude is processed a lot of product is obtained. Gasoline is used to power most internal combustion engines. Some chemicals useful for manufacturing plastics, drugs e.t.c are also derived from the processed crude.
Learn more:
Harnessing fossil fuel brainly.com/question/9231468
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air, water, and ground pollution! hope o helped
Answer:
a. Coded for on the X and Y chromosomes
b. Coded for on the X but not Y chromosome
c. Coded for on the Y but not X chromosome
Explanation:
The X and Y chromosomes are the sex chromosomes as they are involved in sex determination. All the genes that are present on the X and Y chromosomes are inherited along with these chromosomes and therefore, exhibit sex-linked inheritance.
X and Y chromosomes share a homologous region. Therefore, the sex-linked genes are defined as the ones present on both X and Y chromosomes as well as the ones that are present on either X or Y chromosomes.
For example, the gene for hemophilia is present on the X chromosome; but not on the Y chromosome. The SRY gene is present only on the Y chromosome.
