Correct answer: D
A pollen is where male gametes are produced and so the number of chromosomes, as we are talking about gametes, is n. This means that the grain of pollen will only have a copy of each gene, and therefore only one allele for each gene - one S, and one T or t. So, the possible combinations are ST and St.
Answer:
e) Invertebrates lack a nervous system
Explanation:
One of the main characteristics of invertebrates is that they don't have a backbone. Backbones belong to the skeletal system. A totally different story is the nervous system which runs inside the backbone. Although the more complex nervous systems appear in vertebrates the simply fact of having eyes like crabs or insects implies having a nervous system that can control them.
Answer:
d
Explanation:
because when you plough your field for crops to grow rain falls for the crops to yeild well
Answer:
mutagens in the environment, such as tobacco smoke and certain pesticides
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