Which are the special proteins in muscles that contract and relax to cause movement?

 

True. Hormones are chemicals secreted and regulated by the endocrine system.

In all plants and animal cells chromosomes are located in the Nucleus of the cells.

The Chromosomes are thread like structures present in the nucleus of the cells which are made up of proteins and a single molecule of DNA.

Their function is to carry the characteristic features of parent cells to daughter cells. 

The small intestine is the main area of the GI tract for absorption.

The small intestine has three separate sections. Theyare :

1. The duodenum

2. Jejunum and

3. Ileum.

Hence, the majority of nutrient absorption occurs in the duodenum and jejunum of small intestine.

In flowering plants one sperm nucleus fertilizes the egg and the other sperm nucleus fuses with two other nuclei found within the ovule, thus forming triploid endosperm.

Hence, double fertilization is unique to flowering plants.

Genetic drift or allelic drift is the change in the relative frequency in which a gene variant (allele) occurs in a population due to random sampling and chance.

When is genetic drift a major factor in evolution is

* When there is low gene flow.

* When there is no selective pressure.

* When there is a bottleneck.

Decomposers are organisms that break down dead or decaying organisms, and in doing so, they carry out the natural process of decomposition.

The statement "Decomposers are those organisms that recycle matter in the ecosystem" describes decomposers.

Tuber is considered as a modified stem. These type of stems carry out special functions that are important for the plant to survive. Tubers serves as a food reserve and bearing buds wherein new plants can grow.